diff --git a/packages/app/cypress/e2e/overview.cy.ts b/packages/app/cypress/e2e/overview.cy.ts
index 94f91c12..f5c6165e 100644
--- a/packages/app/cypress/e2e/overview.cy.ts
+++ b/packages/app/cypress/e2e/overview.cy.ts
@@ -67,7 +67,7 @@ function expectNoVisibleDatesOrSnapshot() {
       // Next.js RSC payload scripts retain evidence dates for reproducibility.
       // Assert only against rendered page text, not serialized script/style data.
       const clone = body.cloneNode(true) as HTMLElement;
-      clone.querySelectorAll('script, style').forEach((node) => node.remove());
+      clone.querySelectorAll('script, style, .sr-only').forEach((node) => node.remove());
       return clone.textContent ?? '';
     })
     .should((text) => {
@@ -114,6 +114,137 @@ function textRect(element: Element) {
 }
 
 describe('Overview page', () => {
+  it('switches between B200 and 30-day comparison without losing page state', () => {
+    cy.viewport(1280, 900);
+    cy.visit('/overview');
+
+    cy.get('[data-testid="overview-page"]')
+      .children('[data-testid="overview-comparison-switcher"]')
+      .should('have.length', 1)
+      .and('have.class', 'justify-center');
+    cy.get('[data-testid="overview-comparison-switcher"]')
+      .should('have.attr', 'aria-label', 'Compare')
+      .within(() => {
+        cy.get('[data-overview-comparison="hardware"]')
+          .should('have.attr', 'aria-current', 'true')
+          .and('match', 'span')
+          .and('have.text', 'vs B200')
+          .then(([active]) => {
+            const style = getComputedStyle(active);
+            expect(style.borderBottomWidth).to.equal('2px');
+            expect(style.backgroundColor).to.match(/rgba\(0, 0, 0, 0\)|transparent/);
+          });
+        cy.get('[data-overview-comparison="history"]')
+          .should('have.attr', 'href', '/overview?compare=30d')
+          .and('have.text', '30-day change')
+          .click();
+      });
+
+    cy.location('search').should('eq', '?compare=30d');
+    cy.get('[data-testid="overview-comparison-switcher"]')
+      .find('[data-overview-comparison="history"]')
+      .should('have.attr', 'aria-current', 'true')
+      .and('match', 'span');
+    cy.get('[data-testid="overview-desktop-matrix"] thead').should('contain.text', 'B200');
+    cy.get('[data-testid="overview-desktop-matrix"] thead').should('not.contain.text', 'Reference');
+
+    cy.get('[data-testid="overview-tier-switcher"]')
+      .contains('a', '100')
+      .should('have.attr', 'href', '/overview?tier=100&compare=30d');
+    cy.get('[data-testid="overview-engine-scope-switcher"]')
+      .find('[data-overview-engine-scope="all"]')
+      .should('have.attr', 'href', '/overview?engine=all&compare=30d');
+    cy.get('[data-testid="language-toggle"]')
+      .should('have.attr', 'href', '/zh/overview?compare=30d')
+      .click();
+    cy.location('pathname').should('eq', '/zh/overview');
+    cy.location('search').should('eq', '?compare=30d');
+    cy.get('[data-testid="overview-comparison-switcher"]')
+      .should('have.attr', 'aria-label', '对比方式')
+      .within(() => {
+        cy.get('[data-overview-comparison="hardware"]').should('have.text', '对比 B200');
+        cy.get('[data-overview-comparison="history"]')
+          .should('have.attr', 'aria-current', 'true')
+          .and('have.text', '30 天变化');
+      });
+    cy.contains('当前成本及其相对 30–60 天前最近一次有效平台结果的变化。').should('exist');
+    cy.contains('缺少有效 30 天对比的平台仅显示当前成本。').should('exist');
+  });
+
+  it('compares each platform with its own validated result from 30–60 days earlier', () => {
+    cy.viewport(1280, 900);
+    cy.visit('/overview?compare=30d');
+
+    desktopModel('Qwen-3.5-397B-A17B', SINGLE_TURN).within(() => {
+      // Unlike the hardware view, B200 is a normal platform in the historical
+      // view and receives its own change badge and heat-map tint.
+      platform('b200')
+        .find('[data-testid="overview-cost-delta"]')
+        .as('b200HistoryDelta')
+        .should('have.attr', 'data-history-status', 'comparable')
+        .and('have.attr', 'data-cost-polarity', 'cheaper')
+        .and('contain.text', '-17%');
+      cy.get('@b200HistoryDelta')
+        .should(($badge) => {
+          expect($badge).not.to.have.attr('aria-label');
+        })
+        .find('.sr-only')
+        .should('have.text', '17% cheaper than this platform’s Jun 10 result');
+      platform('mi355x')
+        .find('[data-testid="overview-cost-delta"]')
+        .should('have.attr', 'data-history-status', 'comparable')
+        .and('have.attr', 'data-cost-polarity', 'cheaper')
+        .and('contain.text', '-25%');
+      platform('b300').find('[data-testid="overview-cost-delta"]').should('not.exist');
+      platform('b300').then(([cell]) => {
+        expect(getComputedStyle(cell.closest('td')!).backgroundColor).to.match(
+          /rgba\(0, 0, 0, 0\)|transparent/,
+        );
+      });
+      platform('gb200').find('[data-testid="overview-cost-delta"]').should('not.exist');
+    });
+
+    desktopModel('DeepSeek-V4-Pro', AGENTX).within(() => {
+      platform('b200')
+        .find('[data-testid="overview-cost-delta"]')
+        .should('have.attr', 'data-history-status', 'comparable');
+      platform('mi355x')
+        .find('[data-testid="overview-cost-delta"]')
+        .should('have.attr', 'data-history-status', 'comparable');
+    });
+
+    cy.contains(
+      'Current cost and change versus the latest validated platform result 30–60 days earlier.',
+    ).should('exist');
+    cy.get('[data-testid="overview-cost-delta"]').should('not.contain.text', '∞');
+    cy.contains('Platforms without a valid 30-day comparison show current cost only.').should(
+      'exist',
+    );
+    expectNoVisibleDatesOrSnapshot();
+  });
+
+  it('keeps the historical comparison complete and non-scrolling across desktop, tablet and phone', () => {
+    for (const width of [320, 390, 768, 1024, 1279, 1280, 1440]) {
+      cy.viewport(width, 900);
+      cy.visit('/overview?compare=30d');
+
+      cy.get('[data-testid="overview-comparison-switcher"]')
+        .should('be.visible')
+        .find('[data-overview-comparison]')
+        .each(($option) => {
+          expect($option[0].getBoundingClientRect().height).to.be.at.least(44);
+        });
+      cy.get('[data-testid="overview-cost-delta"][data-hardware="b200"]').should('exist');
+      expectNoHorizontalOverflow();
+      if (width < 1280) {
+        expectNoHorizontalScroller('overview-mobile-list');
+        expectNoHorizontalScroller('overview-comparison-switcher');
+      } else {
+        expectNoHorizontalScroller('overview-desktop-matrix');
+      }
+    }
+  });
+
   it('defaults to community engine scope and switches with canonical links preserving tier and locale', () => {
     cy.viewport(1280, 900);
     cy.visit('/overview');
diff --git a/packages/app/cypress/fixtures/api/overview-history-rows.json b/packages/app/cypress/fixtures/api/overview-history-rows.json
new file mode 100644
index 00000000..3671581f
--- /dev/null
+++ b/packages/app/cypress/fixtures/api/overview-history-rows.json
@@ -0,0 +1,206 @@
+{
+  "Qwen-3.5-397B-A17B": [
+    {
+      "id": 1001,
+      "hardware": "b200",
+      "framework": "sglang",
+      "model": "qwen3.5",
+      "precision": "fp4",
+      "spec_method": "mtp",
+      "disagg": false,
+      "is_multinode": false,
+      "prefill_tp": 8,
+      "prefill_ep": 1,
+      "prefill_dp_attention": false,
+      "prefill_num_workers": 1,
+      "decode_tp": 8,
+      "decode_ep": 1,
+      "decode_dp_attention": false,
+      "decode_num_workers": 1,
+      "num_prefill_gpu": 8,
+      "num_decode_gpu": 8,
+      "benchmark_type": "single_turn",
+      "isl": 8192,
+      "osl": 1024,
+      "conc": 8,
+      "offload_mode": "off",
+      "image": null,
+      "metrics": {
+        "median_intvty": 40,
+        "tput_per_gpu": 6000,
+        "output_tput_per_gpu": 667
+      },
+      "date": "2026-06-10",
+      "run_url": null
+    },
+    {
+      "id": 1002,
+      "hardware": "b200",
+      "framework": "sglang",
+      "model": "qwen3.5",
+      "precision": "fp4",
+      "spec_method": "mtp",
+      "disagg": false,
+      "is_multinode": false,
+      "prefill_tp": 8,
+      "prefill_ep": 1,
+      "prefill_dp_attention": false,
+      "prefill_num_workers": 1,
+      "decode_tp": 8,
+      "decode_ep": 1,
+      "decode_dp_attention": false,
+      "decode_num_workers": 1,
+      "num_prefill_gpu": 8,
+      "num_decode_gpu": 8,
+      "benchmark_type": "single_turn",
+      "isl": 8192,
+      "osl": 1024,
+      "conc": 24,
+      "offload_mode": "off",
+      "image": null,
+      "metrics": {
+        "median_intvty": 80,
+        "tput_per_gpu": 4500,
+        "output_tput_per_gpu": 500
+      },
+      "date": "2026-06-10",
+      "run_url": null
+    },
+    {
+      "id": 1003,
+      "hardware": "mi355x",
+      "framework": "sglang",
+      "model": "qwen3.5",
+      "precision": "fp8",
+      "spec_method": "mtp",
+      "disagg": false,
+      "is_multinode": false,
+      "prefill_tp": 8,
+      "prefill_ep": 1,
+      "prefill_dp_attention": false,
+      "prefill_num_workers": 1,
+      "decode_tp": 8,
+      "decode_ep": 1,
+      "decode_dp_attention": false,
+      "decode_num_workers": 1,
+      "num_prefill_gpu": 8,
+      "num_decode_gpu": 8,
+      "benchmark_type": "single_turn",
+      "isl": 8192,
+      "osl": 1024,
+      "conc": 12,
+      "offload_mode": "off",
+      "image": null,
+      "metrics": {
+        "median_intvty": 50,
+        "tput_per_gpu": 5000,
+        "output_tput_per_gpu": 568
+      },
+      "date": "2026-06-12",
+      "run_url": null
+    },
+    {
+      "id": 1004,
+      "hardware": "mi355x",
+      "framework": "sglang",
+      "model": "qwen3.5",
+      "precision": "fp8",
+      "spec_method": "mtp",
+      "disagg": false,
+      "is_multinode": false,
+      "prefill_tp": 8,
+      "prefill_ep": 1,
+      "prefill_dp_attention": false,
+      "prefill_num_workers": 1,
+      "decode_tp": 8,
+      "decode_ep": 1,
+      "decode_dp_attention": false,
+      "decode_num_workers": 1,
+      "num_prefill_gpu": 8,
+      "num_decode_gpu": 8,
+      "benchmark_type": "single_turn",
+      "isl": 8192,
+      "osl": 1024,
+      "conc": 24,
+      "offload_mode": "off",
+      "image": null,
+      "metrics": {
+        "median_intvty": 120,
+        "tput_per_gpu": 3900,
+        "output_tput_per_gpu": 443
+      },
+      "date": "2026-06-12",
+      "run_url": null
+    }
+  ],
+  "DeepSeek-V4-Pro": [
+    {
+      "id": 1005,
+      "hardware": "b200",
+      "framework": "sglang",
+      "model": "dsv4",
+      "precision": "fp4",
+      "spec_method": "mtp",
+      "disagg": false,
+      "is_multinode": false,
+      "prefill_tp": 8,
+      "prefill_ep": 1,
+      "prefill_dp_attention": false,
+      "prefill_num_workers": 1,
+      "decode_tp": 8,
+      "decode_ep": 1,
+      "decode_dp_attention": false,
+      "decode_num_workers": 1,
+      "num_prefill_gpu": 8,
+      "num_decode_gpu": 8,
+      "benchmark_type": "agentic_traces",
+      "isl": null,
+      "osl": null,
+      "conc": 8,
+      "offload_mode": "off",
+      "image": null,
+      "metrics": {
+        "p90_itl": 0.02,
+        "p90_ttlt": 120,
+        "tput_per_gpu": 6000,
+        "output_tput_per_gpu": 667
+      },
+      "date": "2026-06-10",
+      "run_url": null
+    },
+    {
+      "id": 1006,
+      "hardware": "mi355x",
+      "framework": "sglang",
+      "model": "dsv4",
+      "precision": "fp4",
+      "spec_method": "mtp",
+      "disagg": false,
+      "is_multinode": false,
+      "prefill_tp": 8,
+      "prefill_ep": 1,
+      "prefill_dp_attention": false,
+      "prefill_num_workers": 1,
+      "decode_tp": 8,
+      "decode_ep": 1,
+      "decode_dp_attention": false,
+      "decode_num_workers": 1,
+      "num_prefill_gpu": 8,
+      "num_decode_gpu": 8,
+      "benchmark_type": "agentic_traces",
+      "isl": null,
+      "osl": null,
+      "conc": 8,
+      "offload_mode": "off",
+      "image": null,
+      "metrics": {
+        "p90_itl": 0.02,
+        "p90_ttlt": 130,
+        "tput_per_gpu": 5000,
+        "output_tput_per_gpu": 556
+      },
+      "date": "2026-06-10",
+      "run_url": null
+    }
+  ]
+}
diff --git a/packages/app/cypress/fixtures/api/overview-rows.json b/packages/app/cypress/fixtures/api/overview-rows.json
index 37eafb78..fb4a7979 100644
--- a/packages/app/cypress/fixtures/api/overview-rows.json
+++ b/packages/app/cypress/fixtures/api/overview-rows.json
@@ -680,6 +680,64 @@
       "metrics": { "median_intvty": 120, "tput_per_gpu": 5280, "output_tput_per_gpu": 600 },
       "date": "2026-07-18",
       "run_url": null
+    },
+    {
+      "id": 1005,
+      "hardware": "gb200",
+      "framework": "sglang",
+      "model": "qwen3.5",
+      "precision": "fp8",
+      "spec_method": "mtp",
+      "disagg": false,
+      "is_multinode": false,
+      "prefill_tp": 8,
+      "prefill_ep": 1,
+      "prefill_dp_attention": false,
+      "prefill_num_workers": 1,
+      "decode_tp": 8,
+      "decode_ep": 1,
+      "decode_dp_attention": false,
+      "decode_num_workers": 1,
+      "num_prefill_gpu": 8,
+      "num_decode_gpu": 8,
+      "benchmark_type": "single_turn",
+      "isl": 8192,
+      "osl": 1024,
+      "conc": 8,
+      "offload_mode": "off",
+      "image": null,
+      "metrics": { "median_intvty": 40, "tput_per_gpu": 7000, "output_tput_per_gpu": 778 },
+      "date": "2026-06-15",
+      "run_url": null
+    },
+    {
+      "id": 1006,
+      "hardware": "gb200",
+      "framework": "sglang",
+      "model": "qwen3.5",
+      "precision": "fp8",
+      "spec_method": "mtp",
+      "disagg": false,
+      "is_multinode": false,
+      "prefill_tp": 8,
+      "prefill_ep": 1,
+      "prefill_dp_attention": false,
+      "prefill_num_workers": 1,
+      "decode_tp": 8,
+      "decode_ep": 1,
+      "decode_dp_attention": false,
+      "decode_num_workers": 1,
+      "num_prefill_gpu": 8,
+      "num_decode_gpu": 8,
+      "benchmark_type": "single_turn",
+      "isl": 8192,
+      "osl": 1024,
+      "conc": 24,
+      "offload_mode": "off",
+      "image": null,
+      "metrics": { "median_intvty": 80, "tput_per_gpu": 5250, "output_tput_per_gpu": 583 },
+      "date": "2026-06-15",
+      "run_url": null
     }
   ],
   "GLM-5.2": [
diff --git a/packages/app/src/app/(dashboard)/overview/page.tsx b/packages/app/src/app/(dashboard)/overview/page.tsx
index 072858cf..336b0284 100644
--- a/packages/app/src/app/(dashboard)/overview/page.tsx
+++ b/packages/app/src/app/(dashboard)/overview/page.tsx
@@ -4,7 +4,11 @@ import { SITE_NAME, SITE_URL } from '@semianalysisai/inferencex-constants';
 
 import { OverviewPageContent } from '@/components/overview/overview-page';
 import { enAlternates } from '@/lib/i18n';
-import { resolveOverviewEngineScope, resolveOverviewTier } from '@/lib/overview-data';
+import {
+  resolveOverviewComparisonMode,
+  resolveOverviewEngineScope,
+  resolveOverviewTier,
+} from '@/lib/overview-data';
 import { getOverviewPageData } from '@/lib/overview-data.server';
 
 export const dynamic = 'force-dynamic';
@@ -38,6 +42,7 @@ export default async function OverviewPage({ searchParams }: Props) {
   const data = await getOverviewPageData(
     resolveOverviewTier(sp.tier),
     resolveOverviewEngineScope(sp.engine),
+    resolveOverviewComparisonMode(sp.compare),
   );
   return <OverviewPageContent data={data} locale="en" />;
 }
diff --git a/packages/app/src/app/zh/(dashboard)/overview/page.tsx b/packages/app/src/app/zh/(dashboard)/overview/page.tsx
index aa867f57..90736695 100644
--- a/packages/app/src/app/zh/(dashboard)/overview/page.tsx
+++ b/packages/app/src/app/zh/(dashboard)/overview/page.tsx
@@ -4,7 +4,11 @@ import { SITE_NAME, SITE_URL } from '@semianalysisai/inferencex-constants';
 
 import { OverviewPageContent } from '@/components/overview/overview-page';
 import { ZH_OG_LOCALE, zhAlternates } from '@/lib/i18n';
-import { resolveOverviewEngineScope, resolveOverviewTier } from '@/lib/overview-data';
+import {
+  resolveOverviewComparisonMode,
+  resolveOverviewEngineScope,
+  resolveOverviewTier,
+} from '@/lib/overview-data';
 import { getOverviewPageData } from '@/lib/overview-data.server';
 
 export const dynamic = 'force-dynamic';
@@ -39,6 +43,7 @@ export default async function ZhOverviewPage({ searchParams }: Props) {
   const data = await getOverviewPageData(
     resolveOverviewTier(sp.tier),
     resolveOverviewEngineScope(sp.engine),
+    resolveOverviewComparisonMode(sp.compare),
   );
   return <OverviewPageContent data={data} locale="zh" />;
 }
diff --git a/packages/app/src/components/overview/overview-page.tsx b/packages/app/src/components/overview/overview-page.tsx
index 3e1202d9..18a4edfb 100644
--- a/packages/app/src/components/overview/overview-page.tsx
+++ b/packages/app/src/components/overview/overview-page.tsx
@@ -5,6 +5,7 @@ import type { OverviewPageData } from '@/lib/overview-data';
 import {
   DesktopOverviewMatrix,
   MobileOverviewList,
+  OverviewComparisonSwitcher,
   OverviewEngineScopeSwitcher,
   OverviewMethodology,
   OverviewTierSwitcher,
@@ -26,7 +27,7 @@ export function OverviewPageContent({ data, locale }: OverviewPageProps) {
   const formatters = overviewFormatters(locale);
 
   return (
-    <section className="flex flex-col gap-4">
+    <section data-testid="overview-page" className="flex flex-col gap-4">
       <Card>
         <header>
           {/* Two rows at every width: the title, then the metric it is
@@ -77,12 +78,14 @@ export function OverviewPageContent({ data, locale }: OverviewPageProps) {
             <OverviewTierSwitcher
               tier={data.tier}
               engineScope={data.engineScope}
+              comparisonMode={data.comparisonMode}
               locale={locale}
               strings={strings}
             />
             <OverviewEngineScopeSwitcher
               engineScope={data.engineScope}
               tier={data.tier}
+              comparisonMode={data.comparisonMode}
               locale={locale}
               strings={strings}
             />
@@ -90,6 +93,14 @@ export function OverviewPageContent({ data, locale }: OverviewPageProps) {
         </header>
       </Card>
 
+      <OverviewComparisonSwitcher
+        comparisonMode={data.comparisonMode}
+        engineScope={data.engineScope}
+        tier={data.tier}
+        locale={locale}
+        strings={strings}
+      />
+
       {/* Official-only summary; uploaded runs remain in the linked dashboard. */}
       {/* Clipped on phones for the rounded corners; visible from xl so the
           desktop matrix header can stick to the page as it scrolls. */}
@@ -99,14 +110,16 @@ export function OverviewPageContent({ data, locale }: OverviewPageProps) {
           locale={locale}
           formatters={formatters}
           strings={strings}
+          comparisonMode={data.comparisonMode}
         />
         <MobileOverviewList
           models={data.models}
           locale={locale}
           formatters={formatters}
           strings={strings}
+          comparisonMode={data.comparisonMode}
         />
-        <OverviewMethodology strings={strings} />
+        <OverviewMethodology strings={strings} comparisonMode={data.comparisonMode} />
       </Card>
     </section>
   );
diff --git a/packages/app/src/components/overview/overview-scorecard.tsx b/packages/app/src/components/overview/overview-scorecard.tsx
index c4bdba29..a45eef8d 100644
--- a/packages/app/src/components/overview/overview-scorecard.tsx
+++ b/packages/app/src/components/overview/overview-scorecard.tsx
@@ -1,6 +1,8 @@
 import {
   OVERVIEW_TIERS,
+  type OverviewComparisonMode,
   type OverviewEngineScope,
+  type OverviewHistoricalComparison,
   type OverviewModelSummary,
   type OverviewPlatformResult,
   type OverviewTier,
@@ -9,6 +11,7 @@ import {
   buildOverviewDashboardHref,
   detailHref,
   overviewEngineScopeHref,
+  overviewHref,
   overviewTierHref,
 } from '@/lib/overview-links';
 
@@ -34,8 +37,15 @@ export const OVERVIEW_STRINGS = {
       all: 'All Platforms',
       community: 'Open Source Community Engines (vLLM/SGLang)',
     },
+    comparisonNavLabel: 'Compare',
+    comparisonOptions: {
+      hardware: 'vs B200',
+      history: '30-day change',
+    },
     caption:
       'Cost per million total tokens from each platform’s best observed serving envelope for the scenario shown with each model.',
+    historyCaption:
+      'Current cost and change versus the latest validated platform result 30–60 days earlier.',
     modelHeader: 'Model · Scenario',
     scenarioLabels: {
       single_turn_8k1k: '8K/1K',
@@ -65,6 +75,11 @@ export const OVERVIEW_STRINGS = {
       `${pct} ${cheaper ? 'cheaper' : 'more expensive'} than B200`,
     costDeltaEvenAria: 'About the same cost as B200',
     noBaselineAria: 'No B200 baseline to compare against',
+    historicalDeltaAria: (pct: string, cheaper: boolean, baselineDate: string) =>
+      `${pct} ${cheaper ? 'cheaper' : 'more expensive'} than this platform’s ${baselineDate} result`,
+    historicalEvenAria: (baselineDate: string) =>
+      `About the same cost as this platform’s ${baselineDate} result`,
+    historyCellStateLegend: 'Platforms without a valid 30-day comparison show current cost only.',
     referenceHeader: 'Reference',
   },
   zh: {
@@ -81,7 +96,13 @@ export const OVERVIEW_STRINGS = {
       all: '所有平台',
       community: '开源社区引擎（vLLM/SGLang）',
     },
+    comparisonNavLabel: '对比方式',
+    comparisonOptions: {
+      hardware: '对比 B200',
+      history: '30 天变化',
+    },
     caption: '按各模型标注的场景，基于各平台最佳观测服务包络线计算每百万总 token 成本。',
+    historyCaption: '当前成本及其相对 30–60 天前最近一次有效平台结果的变化。',
     modelHeader: '模型 · 场景',
     scenarioLabels: {
       single_turn_8k1k: '8K/1K',
@@ -109,6 +130,10 @@ export const OVERVIEW_STRINGS = {
     costDeltaAria: (pct: string, cheaper: boolean) => `比 B200 ${cheaper ? '便宜' : '昂贵'} ${pct}`,
     costDeltaEvenAria: '与 B200 成本基本持平',
     noBaselineAria: '缺少可比较的 B200 基线',
+    historicalDeltaAria: (pct: string, cheaper: boolean, baselineDate: string) =>
+      `比该平台 ${baselineDate} 的结果${cheaper ? '便宜' : '昂贵'} ${pct}`,
+    historicalEvenAria: (baselineDate: string) => `与该平台 ${baselineDate} 的结果成本基本持平`,
+    historyCellStateLegend: '缺少有效 30 天对比的平台仅显示当前成本。',
     referenceHeader: '基准',
   },
 } as const;
@@ -185,7 +210,7 @@ function CellMissing({ hardware, reason }: { hardware: string; reason: string })
 const COST_DELTA_NEUTRAL_BAND = 0.05;
 /** Magnitudes at or beyond this saturate the shade ramp. */
 const COST_DELTA_SATURATION = 0.5;
-// `no-baseline` (∞) is neutral gray, never red/green: a missing B200 baseline
+// Missing comparison evidence is neutral gray, never red/green: availability
 // is not a better/worse judgment.
 const COST_DELTA_CLASS = {
   cheaper: 'text-emerald-700 dark:text-emerald-400',
@@ -196,7 +221,7 @@ const COST_DELTA_CLASS = {
 const COST_DELTA_HUE = {
   cheaper: '16 185 129',
   pricier: '239 68 68',
-  // Parity and "no B200 baseline" both read as neutral gray.
+  // Parity and missing comparison evidence both read as neutral gray.
   even: '148 163 184',
   'no-baseline': '148 163 184',
 } as const;
@@ -205,11 +230,76 @@ const COST_DELTA_NEUTRAL_ALPHA = '0.10';
 
 type CostDeltaPolarity = keyof typeof COST_DELTA_CLASS;
 
+interface DisplayedComparison {
+  status: Exclude<OverviewHistoricalComparison['status'], 'no_newer_result'>;
+  pct: number | null;
+  baselineDate: string | null;
+}
+
+function displayedComparison(
+  platform: OverviewPlatformResult,
+  comparisonMode: OverviewComparisonMode,
+): DisplayedComparison | null {
+  if (platform.costPerMtok === null) return null;
+  if (comparisonMode === 'history') {
+    const comparison = platform.historicalComparison;
+    return comparison?.status === 'comparable' && comparison.costDeltaPct !== null
+      ? {
+          status: comparison.status,
+          pct: comparison.costDeltaPct,
+          baselineDate: comparison.baselineDate,
+        }
+      : null;
+  }
+  if (platform.hardware === 'b200') return null;
+  return {
+    status: platform.costVsB200Pct === null ? 'no_baseline' : 'comparable',
+    pct: platform.costVsB200Pct,
+    baselineDate: null,
+  };
+}
+
 function costDeltaPolarity(pct: number): CostDeltaPolarity {
   if (Math.abs(pct) < COST_DELTA_NEUTRAL_BAND) return 'even';
   return pct < 0 ? 'cheaper' : 'pricier';
 }
 
+function comparisonPolarity(comparison: DisplayedComparison): CostDeltaPolarity {
+  return comparison.status !== 'comparable' || comparison.pct === null
+    ? 'no-baseline'
+    : costDeltaPolarity(comparison.pct);
+}
+
+function comparisonAria(
+  comparison: DisplayedComparison,
+  comparisonMode: OverviewComparisonMode,
+  polarity: CostDeltaPolarity,
+  formatters: Formatters,
+  strings: OverviewStrings,
+): string {
+  if (comparison.status === 'no_baseline' || comparison.pct === null) {
+    return strings.noBaselineAria;
+  }
+  if (comparisonMode === 'hardware') {
+    return polarity === 'even'
+      ? strings.costDeltaEvenAria
+      : strings.costDeltaAria(
+          formatters.percentAbs.format(Math.abs(comparison.pct)),
+          polarity === 'cheaper',
+        );
+  }
+
+  const baselineDate =
+    comparison.baselineDate === null ? '' : formatters.shortDate(comparison.baselineDate);
+  return polarity === 'even'
+    ? strings.historicalEvenAria(baselineDate)
+    : strings.historicalDeltaAria(
+        formatters.percentAbs.format(Math.abs(comparison.pct)),
+        polarity === 'cheaper',
+        baselineDate,
+      );
+}
+
 /** Continuous shade: only background alpha tracks the magnitude, so every
  *  cell reads on one ramp instead of stepping through discrete bins. */
 function costDeltaAlpha(pct: number): string {
@@ -224,48 +314,43 @@ function costDeltaAlpha(pct: number): string {
  */
 export function costDeltaCellStyle(
   platform: OverviewPlatformResult,
+  comparisonMode: OverviewComparisonMode = 'hardware',
 ): { backgroundColor: string } | undefined {
-  if (platform.costPerMtok === null) return undefined;
-  // B200 is the baseline: its null delta means "nothing to compare against
-  // itself", not the ∞ state, so it keeps the reference column's own tint.
-  if (platform.hardware === 'b200') return undefined;
-  const pct = platform.costVsB200Pct;
-  const polarity: CostDeltaPolarity = pct === null ? 'no-baseline' : costDeltaPolarity(pct);
+  const comparison = displayedComparison(platform, comparisonMode);
+  if (comparison === null) return undefined;
+  const { pct } = comparison;
+  const polarity = comparisonPolarity(comparison);
   const alpha =
     pct === null || polarity === 'even' ? COST_DELTA_NEUTRAL_ALPHA : costDeltaAlpha(pct);
   return { backgroundColor: `rgb(${COST_DELTA_HUE[polarity]} / ${alpha})` };
 }
 
-/** Relative-to-B200 badge. `pct === null` means the row's B200 baseline is
- *  unavailable: the badge shows a neutral `∞` instead of a percentage. */
+/** Relative comparison badge. Missing B200 evidence stays neutral and uses
+ *  `∞` instead of manufacturing a percentage. */
 function CostDeltaBadge({
-  pct,
+  comparison,
+  comparisonMode,
   hardware,
   formatters,
   strings,
   phoneRow,
 }: {
-  pct: number | null;
+  comparison: DisplayedComparison;
+  comparisonMode: OverviewComparisonMode;
   hardware: string;
   formatters: Formatters;
   strings: OverviewStrings;
   phoneRow: boolean;
 }) {
-  const polarity: CostDeltaPolarity = pct === null ? 'no-baseline' : costDeltaPolarity(pct);
-  const aria =
-    pct === null
-      ? strings.noBaselineAria
-      : polarity === 'even'
-        ? strings.costDeltaEvenAria
-        : strings.costDeltaAria(
-            formatters.percentAbs.format(Math.abs(pct)),
-            polarity === 'cheaper',
-          );
+  const { pct, status } = comparison;
+  const polarity = comparisonPolarity(comparison);
+  const aria = comparisonAria(comparison, comparisonMode, polarity, formatters, strings);
   return (
     <span
       data-testid="overview-cost-delta"
       data-hardware={hardware}
       data-cost-polarity={polarity}
+      data-history-status={comparisonMode === 'history' ? status : undefined}
       title={aria}
       // The cell behind it carries the shade, so the badge itself stays
       // untinted — two washes of the same hue would double up.
@@ -285,6 +370,7 @@ function CellValue({
   member,
   formatters,
   strings,
+  comparisonMode,
   phoneRow = false,
 }: {
   locale: OverviewLocale;
@@ -292,6 +378,7 @@ function CellValue({
   member: OverviewPlatformResult;
   formatters: Formatters;
   strings: OverviewStrings;
+  comparisonMode: OverviewComparisonMode;
   phoneRow?: boolean;
 }) {
   const { value, config, evidenceDate, evidenceTopologies } = member.read;
@@ -343,6 +430,7 @@ function CellValue({
       ? null
       : strings.rawDashboardAria(evidenceDateLabel, model.modelLabel, stack);
   const costText = formattedValue;
+  const comparison = displayedComparison(member, comparisonMode);
   return (
     <div className="min-w-0 space-y-0.5 text-sm">
       {/* Fixed cost | delta grids keep comparisons scannable on desktop and phones;
@@ -390,9 +478,10 @@ function CellValue({
             </a>
           )}
         </span>
-        {member.hardware === 'b200' ? null : (
+        {comparison === null ? null : (
           <CostDeltaBadge
-            pct={member.costVsB200Pct}
+            comparison={comparison}
+            comparisonMode={comparisonMode}
             hardware={member.hardware}
             formatters={formatters}
             strings={strings}
@@ -424,6 +513,7 @@ function PlatformCell(props: {
   platform: OverviewPlatformResult;
   formatters: Formatters;
   strings: OverviewStrings;
+  comparisonMode: OverviewComparisonMode;
   phoneRow?: boolean;
 }) {
   return (
@@ -434,6 +524,7 @@ function PlatformCell(props: {
         member={props.platform}
         formatters={props.formatters}
         strings={props.strings}
+        comparisonMode={props.comparisonMode}
         phoneRow={props.phoneRow}
       />
     </div>
@@ -459,14 +550,23 @@ interface SurfaceProps {
   locale: OverviewLocale;
   formatters: Formatters;
   strings: OverviewStrings;
+  comparisonMode: OverviewComparisonMode;
 }
 
-export function DesktopOverviewMatrix({ models, locale, formatters, strings }: SurfaceProps) {
+export function DesktopOverviewMatrix({
+  models,
+  locale,
+  formatters,
+  strings,
+  comparisonMode,
+}: SurfaceProps) {
   const platforms = models[0]?.platforms ?? [];
   return (
     <div className="hidden xl:block">
       <table data-testid="overview-desktop-matrix" className="w-full border-collapse text-sm">
-        <caption className="sr-only">{strings.caption}</caption>
+        <caption className="sr-only">
+          {comparisonMode === 'history' ? strings.historyCaption : strings.caption}
+        </caption>
         <colgroup>
           <col className="w-[22%]" />
           {platforms.map((platform) => (
@@ -486,9 +586,9 @@ export function DesktopOverviewMatrix({ models, locale, formatters, strings }: S
               <th
                 key={platform.hardware}
                 scope="col"
-                className={`px-3 py-2 text-left font-semibold ${platform.hardware === 'b200' ? 'bg-muted' : 'bg-card'}`}
+                className={`px-3 py-2 text-left font-semibold ${comparisonMode === 'hardware' && platform.hardware === 'b200' ? 'bg-muted' : 'bg-card'}`}
               >
-                {platform.hardware === 'b200'
+                {comparisonMode === 'hardware' && platform.hardware === 'b200'
                   ? `${platform.hardwareLabel} · ${strings.referenceHeader}`
                   : platform.hardwareLabel}
               </th>
@@ -523,8 +623,8 @@ export function DesktopOverviewMatrix({ models, locale, formatters, strings }: S
               {model.platforms.map((platform) => (
                 <td
                   key={platform.hardware}
-                  style={costDeltaCellStyle(platform)}
-                  className={`px-3 py-4 align-top ${platform.hardware === 'b200' ? 'bg-muted/30' : ''}`}
+                  style={costDeltaCellStyle(platform, comparisonMode)}
+                  className={`px-3 py-4 align-top ${comparisonMode === 'hardware' && platform.hardware === 'b200' ? 'bg-muted/30' : ''}`}
                 >
                   <PlatformCell
                     locale={locale}
@@ -532,6 +632,7 @@ export function DesktopOverviewMatrix({ models, locale, formatters, strings }: S
                     platform={platform}
                     formatters={formatters}
                     strings={strings}
+                    comparisonMode={comparisonMode}
                   />
                 </td>
               ))}
@@ -543,7 +644,13 @@ export function DesktopOverviewMatrix({ models, locale, formatters, strings }: S
   );
 }
 
-export function MobileOverviewList({ models, locale, formatters, strings }: SurfaceProps) {
+export function MobileOverviewList({
+  models,
+  locale,
+  formatters,
+  strings,
+  comparisonMode,
+}: SurfaceProps) {
   return (
     <ul data-testid="overview-mobile-list" className="divide-y divide-border/50 xl:hidden">
       {models.map((model) => (
@@ -561,7 +668,7 @@ export function MobileOverviewList({ models, locale, formatters, strings }: Surf
                   key={platform.hardware}
                   data-testid="overview-mobile-platform-row"
                   data-hardware={platform.hardware}
-                  style={costDeltaCellStyle(platform)}
+                  style={costDeltaCellStyle(platform, comparisonMode)}
                   className="grid min-w-0 grid-cols-[4.25rem_minmax(0,1fr)] gap-x-3 border-b border-border/30 py-1.5 last:border-b-0"
                 >
                   <span
@@ -576,6 +683,7 @@ export function MobileOverviewList({ models, locale, formatters, strings }: Surf
                     platform={platform}
                     formatters={formatters}
                     strings={strings}
+                    comparisonMode={comparisonMode}
                     phoneRow
                   />
                 </div>
@@ -604,11 +712,13 @@ export function MobileOverviewList({ models, locale, formatters, strings }: Surf
 export function OverviewTierSwitcher({
   tier,
   engineScope,
+  comparisonMode,
   locale,
   strings,
 }: {
   tier: OverviewTier;
   engineScope: OverviewEngineScope;
+  comparisonMode: OverviewComparisonMode;
   locale: OverviewLocale;
   strings: OverviewStrings;
 }) {
@@ -633,7 +743,7 @@ export function OverviewTierSwitcher({
           ) : (
             <a
               key={option}
-              href={overviewTierHref(locale, option, engineScope)}
+              href={overviewTierHref(locale, option, engineScope, comparisonMode)}
               className={`${optionClass} text-muted-foreground transition-colors hover:bg-muted hover:text-foreground`}
             >
               {option}
@@ -650,11 +760,13 @@ export function OverviewTierSwitcher({
 export function OverviewEngineScopeSwitcher({
   engineScope,
   tier,
+  comparisonMode,
   locale,
   strings,
 }: {
   engineScope: OverviewEngineScope;
   tier: OverviewTier;
+  comparisonMode: OverviewComparisonMode;
   locale: OverviewLocale;
   strings: OverviewStrings;
 }) {
@@ -683,7 +795,7 @@ export function OverviewEngineScopeSwitcher({
             <a
               key={option}
               data-overview-engine-scope={option}
-              href={overviewEngineScopeHref(locale, option, tier)}
+              href={overviewEngineScopeHref(locale, option, tier, comparisonMode)}
               className={`${optionClass} text-muted-foreground transition-colors hover:bg-muted hover:text-foreground`}
             >
               {strings.engineScopeOptions[option]}
@@ -695,13 +807,69 @@ export function OverviewEngineScopeSwitcher({
   );
 }
 
-export function OverviewMethodology({ strings }: { strings: OverviewStrings }) {
+export function OverviewComparisonSwitcher({
+  comparisonMode,
+  engineScope,
+  tier,
+  locale,
+  strings,
+}: {
+  comparisonMode: OverviewComparisonMode;
+  engineScope: OverviewEngineScope;
+  tier: OverviewTier;
+  locale: OverviewLocale;
+  strings: OverviewStrings;
+}) {
+  const options: OverviewComparisonMode[] = ['hardware', 'history'];
+  const optionClass =
+    'relative inline-flex min-h-11 min-w-[130px] items-center justify-center whitespace-nowrap border-b-2 border-transparent px-4 py-2 text-sm font-semibold text-muted-foreground transition-colors duration-200 hover:border-muted-foreground/30 focus-visible:outline-none focus-visible:ring-[3px] focus-visible:ring-ring sm:min-w-[140px]';
+  return (
+    <nav
+      data-testid="overview-comparison-switcher"
+      aria-label={strings.comparisonNavLabel}
+      className="flex flex-wrap justify-center gap-x-1 gap-y-1.5 sm:gap-x-1.5"
+    >
+      {options.map((option) =>
+        option === comparisonMode ? (
+          <span
+            key={option}
+            data-overview-comparison={option}
+            aria-current="true"
+            className={`${optionClass} border-secondary text-secondary dark:border-primary dark:text-primary`}
+          >
+            {strings.comparisonOptions[option]}
+          </span>
+        ) : (
+          <a
+            key={option}
+            data-overview-comparison={option}
+            href={overviewHref(locale, tier, engineScope, option)}
+            className={optionClass}
+          >
+            {strings.comparisonOptions[option]}
+          </a>
+        ),
+      )}
+    </nav>
+  );
+}
+
+export function OverviewMethodology({
+  strings,
+  comparisonMode,
+}: {
+  strings: OverviewStrings;
+  comparisonMode: OverviewComparisonMode;
+}) {
   return (
     <div
       data-testid="overview-methodology"
       className="space-y-1 border-t border-border/50 px-4 py-3 text-xs leading-snug text-muted-foreground lg:px-6"
     >
-      <p>{strings.cellStateLegend}</p>
+      {comparisonMode === 'history' ? <p>{strings.historyCaption}</p> : null}
+      <p>
+        {comparisonMode === 'history' ? strings.historyCellStateLegend : strings.cellStateLegend}
+      </p>
       <p>{strings.methodologyNote}</p>
     </div>
   );
diff --git a/packages/app/src/lib/benchmark-data.server.ts b/packages/app/src/lib/benchmark-data.server.ts
index ccc85317..e288596c 100644
--- a/packages/app/src/lib/benchmark-data.server.ts
+++ b/packages/app/src/lib/benchmark-data.server.ts
@@ -19,3 +19,15 @@ export const getCachedBenchmarks = cachedQuery(
   'benchmarks',
   { blobOnly: true },
 );
+
+/** Historical overview snapshots use the same line-level as-of semantics as
+ * the dashboard, cached separately from the absolute-latest read. */
+export const getCachedBenchmarksAsOf = cachedQuery(
+  (dbModelKeys: string[], date: string) => {
+    if (FIXTURES_MODE) return Promise.resolve(loadFixture<BenchmarkRow[]>('benchmarks'));
+
+    return getLatestBenchmarks(getDb(), dbModelKeys, date);
+  },
+  'benchmarks-as-of',
+  { blobOnly: true },
+);
diff --git a/packages/app/src/lib/overview-data.server.test.ts b/packages/app/src/lib/overview-data.server.test.ts
index 2135e0a6..e74d08b7 100644
--- a/packages/app/src/lib/overview-data.server.test.ts
+++ b/packages/app/src/lib/overview-data.server.test.ts
@@ -6,7 +6,12 @@ import type { OverviewPageData } from './overview-data';
 
 /** `throughput` is TOTAL tok/s per GPU — the overview's cost basis. The
  *  output metric is a decoy so a regression to output pricing surfaces here. */
-function row(hardware: string, framework: string, throughput: number): BenchmarkRow {
+function row(
+  hardware: string,
+  framework: string,
+  throughput: number,
+  date = '2026-07-20',
+): BenchmarkRow {
   return {
     id: throughput,
     hardware,
@@ -33,7 +38,7 @@ function row(hardware: string, framework: string, throughput: number): Benchmark
     offload_mode: 'off',
     image: null,
     metrics: { median_intvty: 50, tput_per_gpu: throughput, output_tput_per_gpu: 123 },
-    date: '2026-07-20',
+    date,
     run_url: null,
   };
 }
@@ -85,8 +90,12 @@ describe('getOverviewPageData engine scope forwarding', () => {
 
   it('forwards community scope through live benchmark queries', async () => {
     const getCachedBenchmarks = vi.fn(() => Promise.resolve(rows));
+    const getCachedBenchmarksAsOf = vi.fn();
     vi.doMock('@semianalysisai/inferencex-db/connection', () => ({ FIXTURES_MODE: false }));
-    vi.doMock('@/lib/benchmark-data.server', () => ({ getCachedBenchmarks }));
+    vi.doMock('@/lib/benchmark-data.server', () => ({
+      getCachedBenchmarks,
+      getCachedBenchmarksAsOf,
+    }));
     vi.doMock('@/lib/test-fixtures', () => ({ loadFixture: vi.fn() }));
 
     const { getOverviewPageData } = await import('./overview-data.server');
@@ -98,5 +107,70 @@ describe('getOverviewPageData engine scope forwarding', () => {
       baseline: 'llmd-vllm',
     });
     expect(getCachedBenchmarks).toHaveBeenCalled();
+    expect(getCachedBenchmarksAsOf).not.toHaveBeenCalled();
+  });
+
+  it('loads an as-of snapshot for history mode and rejects baselines older than 60 days', async () => {
+    const currentRows = [...rows, row('b300', 'vllm', 1100)];
+    const historicalRows = [
+      row('mi355x', 'dynamo-vllm', 800, '2026-06-15'),
+      row('b200', 'llmd-vllm', 700, '2026-06-15'),
+      row('b300', 'vllm', 900, '2026-05-20'),
+    ];
+    const getCachedBenchmarks = vi.fn(() => Promise.resolve(currentRows));
+    const getCachedBenchmarksAsOf = vi.fn((_keys: string[], _date: string) =>
+      Promise.resolve(historicalRows),
+    );
+    vi.doMock('@semianalysisai/inferencex-db/connection', () => ({ FIXTURES_MODE: false }));
+    vi.doMock('@/lib/benchmark-data.server', () => ({
+      getCachedBenchmarks,
+      getCachedBenchmarksAsOf,
+    }));
+    vi.doMock('@/lib/test-fixtures', () => ({ loadFixture: vi.fn() }));
+
+    const { getOverviewPageData } = await import('./overview-data.server');
+    const page = await getOverviewPageData(50, 'community', 'history');
+    const qwen = page.models.find((model) => model.model === Model.Qwen3_5);
+    const mi355x = qwen?.platforms.find(({ hardware }) => hardware === 'mi355x');
+    const b300 = qwen?.platforms.find(({ hardware }) => hardware === 'b300');
+
+    expect(page.comparisonMode).toBe('history');
+    expect(page.historicalWindow).toEqual({
+      snapshotDate: '2026-07-20',
+      targetDate: '2026-06-20',
+      earliestDate: '2026-05-21',
+    });
+    expect(getCachedBenchmarksAsOf).toHaveBeenCalled();
+    expect(getCachedBenchmarksAsOf.mock.calls.every(([, date]) => date === '2026-06-20')).toBe(
+      true,
+    );
+    expect(mi355x?.historicalComparison?.status).toBe('comparable');
+    expect(mi355x?.historicalComparison?.baselineDate).toBe('2026-06-15');
+    expect(b300?.historicalComparison?.status).toBe('no_baseline');
+  });
+
+  it('loads separate current and historical fixtures in history mode', async () => {
+    const loadFixture = vi.fn((name: string) =>
+      name === 'overview-history-rows'
+        ? { [Model.Qwen3_5]: [row('mi355x', 'dynamo-vllm', 800, '2026-06-15')] }
+        : { [Model.Qwen3_5]: rows },
+    );
+    const getCachedBenchmarks = vi.fn();
+    const getCachedBenchmarksAsOf = vi.fn();
+    vi.doMock('@semianalysisai/inferencex-db/connection', () => ({ FIXTURES_MODE: true }));
+    vi.doMock('@/lib/benchmark-data.server', () => ({
+      getCachedBenchmarks,
+      getCachedBenchmarksAsOf,
+    }));
+    vi.doMock('@/lib/test-fixtures', () => ({ loadFixture }));
+
+    const { getOverviewPageData } = await import('./overview-data.server');
+    const page = await getOverviewPageData(50, 'community', 'history');
+
+    expect(page.comparisonMode).toBe('history');
+    expect(loadFixture).toHaveBeenCalledWith('overview-rows');
+    expect(loadFixture).toHaveBeenCalledWith('overview-history-rows');
+    expect(getCachedBenchmarks).not.toHaveBeenCalled();
+    expect(getCachedBenchmarksAsOf).not.toHaveBeenCalled();
   });
 });
diff --git a/packages/app/src/lib/overview-data.server.ts b/packages/app/src/lib/overview-data.server.ts
index a5cd42d0..ac1e21e1 100644
--- a/packages/app/src/lib/overview-data.server.ts
+++ b/packages/app/src/lib/overview-data.server.ts
@@ -2,38 +2,73 @@ import { DISPLAY_MODEL_TO_DB } from '@semianalysisai/inferencex-constants';
 import { FIXTURES_MODE } from '@semianalysisai/inferencex-db/connection';
 
 import type { BenchmarkRow } from '@/lib/api';
-import { getCachedBenchmarks } from '@/lib/benchmark-data.server';
+import { getCachedBenchmarks, getCachedBenchmarksAsOf } from '@/lib/benchmark-data.server';
 import { DEFAULT_MODELS } from '@/lib/data-mappings';
 import {
+  assembleOverviewHistoricalPageData,
   assembleOverviewPageData,
+  OVERVIEW_DEFAULT_COMPARISON_MODE,
   OVERVIEW_PRIMARY_TIER,
+  overviewHistoricalWindow,
+  overviewSnapshotDate,
+  type OverviewComparisonMode,
   type OverviewEngineScope,
   type OverviewPageData,
   type OverviewTier,
 } from '@/lib/overview-data';
 import { loadFixture } from '@/lib/test-fixtures';
 
+async function loadRowsByModel(
+  loader: (keys: string[]) => Promise<BenchmarkRow[]>,
+): Promise<Record<string, BenchmarkRow[]>> {
+  const entries = await Promise.all(
+    [...DEFAULT_MODELS].map(async (model) => {
+      const keys = DISPLAY_MODEL_TO_DB[model] ?? [];
+      const rows = keys.length > 0 ? await loader(keys) : [];
+      return [model, rows] as const;
+    }),
+  );
+  return Object.fromEntries(entries);
+}
+
 export async function getOverviewPageData(
   tier: OverviewTier = OVERVIEW_PRIMARY_TIER,
   engineScope: OverviewEngineScope = 'community',
+  comparisonMode: OverviewComparisonMode = OVERVIEW_DEFAULT_COMPARISON_MODE,
 ): Promise<OverviewPageData> {
-  // Synthetic rows go through the same assembler as the live path, so a
-  // contract drift breaks the fixture tests instead of stranding the page.
-  if (FIXTURES_MODE) {
-    return assembleOverviewPageData(
-      loadFixture<Record<string, BenchmarkRow[]>>('overview-rows'),
-      tier,
-      engineScope,
-    );
+  // Synthetic rows go through the same assemblers as the live path, so a
+  // contract drift breaks fixture tests instead of stranding the page.
+  const currentRowsByModel = FIXTURES_MODE
+    ? loadFixture<Record<string, BenchmarkRow[]>>('overview-rows')
+    : await loadRowsByModel(getCachedBenchmarks);
+  if (comparisonMode === 'hardware') {
+    return assembleOverviewPageData(currentRowsByModel, tier, engineScope);
   }
 
-  const entries = await Promise.all(
-    [...DEFAULT_MODELS].map(async (model) => {
-      const keys = DISPLAY_MODEL_TO_DB[model] ?? [];
-      const rows = keys.length > 0 ? await getCachedBenchmarks(keys) : [];
-      return [model, rows] as const;
-    }),
+  const snapshotDate = overviewSnapshotDate(currentRowsByModel, engineScope);
+  if (snapshotDate === null) {
+    return {
+      ...assembleOverviewPageData(currentRowsByModel, tier, engineScope),
+      comparisonMode: 'history',
+    };
+  }
+
+  const window = overviewHistoricalWindow(snapshotDate);
+  const unboundedBaselineRows = FIXTURES_MODE
+    ? loadFixture<Record<string, BenchmarkRow[]>>('overview-history-rows')
+    : await loadRowsByModel((keys) => getCachedBenchmarksAsOf(keys, window.targetDate));
+  const baselineRowsByModel = Object.fromEntries(
+    Object.entries(unboundedBaselineRows).map(([model, rows]) => [
+      model,
+      rows.filter((row) => row.date >= window.earliestDate && row.date <= window.targetDate),
+    ]),
   );
 
-  return assembleOverviewPageData(Object.fromEntries(entries), tier, engineScope);
+  return assembleOverviewHistoricalPageData(
+    currentRowsByModel,
+    baselineRowsByModel,
+    window,
+    tier,
+    engineScope,
+  );
 }
diff --git a/packages/app/src/lib/overview-data.test.ts b/packages/app/src/lib/overview-data.test.ts
index 908246f3..afb17bb0 100644
--- a/packages/app/src/lib/overview-data.test.ts
+++ b/packages/app/src/lib/overview-data.test.ts
@@ -7,13 +7,19 @@ import { dedupeRowsToLatestPerConfig } from '@/components/inference/hooks/useCha
 import type { BenchmarkRow } from './api';
 import { DEFAULT_MODELS, Model, Precision } from './data-mappings';
 import {
+  assembleOverviewHistoricalPageData,
   assembleOverviewPageData,
   buildOverviewModelSummary,
   overviewCostPerMtok,
+  overviewHistoricalWindow,
   overviewScenarioForModel,
+  overviewSnapshotDate,
+  overviewTierEvidenceDate,
+  resolveOverviewComparisonMode,
   resolveOverviewEngineScope,
   resolveOverviewTier,
   type OverviewModelSummary,
+  type OverviewPageData,
 } from './overview-data';
 
 let nextId = 1;
@@ -120,7 +126,28 @@ function headlinePairOf(summary: OverviewModelSummary, id: string) {
   return candidate === undefined || baseline === undefined ? undefined : { candidate, baseline };
 }
 
+function platformFor(
+  page: OverviewPageData,
+  model: Model,
+  scenario: OverviewModelSummary['scenario'],
+  hardware: string,
+) {
+  return page.models
+    .find((summary) => summary.model === model && summary.scenario === scenario)
+    ?.platforms.find((platform) => platform.hardware === hardware);
+}
+
 describe('overview engine scope and scenario selection', () => {
+  it.each([
+    [undefined, 'hardware'],
+    ['hardware', 'hardware'],
+    ['30d', 'history'],
+    [['30d'], 'history'],
+    ['unknown', 'hardware'],
+  ] as const)('resolves comparison mode %j to %s', (raw, expected) => {
+    expect(resolveOverviewComparisonMode(raw)).toBe(expected);
+  });
+
   it('assigns each active model to its configured scenario', () => {
     expect(overviewScenarioForModel(Model.Kimi_K3)).toBe('agentx');
     expect(overviewScenarioForModel(Model.GLM_5_2)).toBe('agentx');
@@ -594,6 +621,208 @@ describe('overview engine scope and scenario selection', () => {
   });
 });
 
+describe('overview historical window', () => {
+  it('anchors the target and floor to the latest database evidence date', () => {
+    expect(overviewHistoricalWindow('2026-08-03')).toEqual({
+      snapshotDate: '2026-08-03',
+      targetDate: '2026-07-04',
+      earliestDate: '2026-06-04',
+    });
+  });
+
+  it('returns the latest date across model buckets', () => {
+    expect(
+      overviewSnapshotDate({
+        a: [row({ date: '2026-07-30' })],
+        b: [row({ date: '2026-08-03' })],
+      }),
+    ).toBe('2026-08-03');
+  });
+
+  it('ignores newer rows that cannot appear in the overview', () => {
+    expect(
+      overviewSnapshotDate({
+        qwen: [
+          row({ date: '2026-07-30' }),
+          row({ date: '2026-08-03', hardware: 'h200' }),
+          row({ date: '2026-08-02', isl: 1024, osl: 1024 }),
+        ],
+      }),
+    ).toBe('2026-07-30');
+  });
+
+  it('ignores newer rows from scenarios excluded by the curated model layout', () => {
+    expect(
+      overviewSnapshotDate({
+        [Model.Kimi_K2_5]: [
+          row({ model: 'kimik2.5', date: '2026-07-30' }),
+          agenticRow(50, 25, 7650, 850, {
+            model: 'kimik2.5',
+            date: '2026-08-03',
+          }),
+        ],
+      }),
+    ).toBe('2026-07-30');
+  });
+
+  it('anchors the snapshot date to rows visible in the active engine scope', () => {
+    const rows = {
+      [Model.Qwen3_5]: [
+        row({ date: '2026-07-30', framework: 'sglang' }),
+        row({ date: '2026-08-03', framework: 'atom' }),
+      ],
+    };
+
+    expect(overviewSnapshotDate(rows, 'community')).toBe('2026-07-30');
+    expect(overviewSnapshotDate(rows, 'all')).toBe('2026-08-03');
+  });
+
+  it('returns null when every model bucket is empty', () => {
+    expect(overviewSnapshotDate({ a: [], b: [] })).toBeNull();
+  });
+
+  it('uses the selected tier evidence date instead of the config latest date', () => {
+    const read = buildOverviewModelSummary(Model.Qwen3_5, [
+      ...frontier([12000, 10000, 8000, 6000], { date: '2026-08-01' }),
+    ]).platforms[0].read;
+
+    expect(
+      overviewTierEvidenceDate({
+        ...read,
+        evidenceDate: { from: '2026-07-03', to: '2026-07-04' },
+      }),
+    ).toBe('2026-07-04');
+    expect(overviewTierEvidenceDate({ ...read, evidenceDate: null })).toBe('2026-08-01');
+  });
+});
+
+describe('assembleOverviewHistoricalPageData', () => {
+  const window = {
+    snapshotDate: '2026-08-03',
+    targetDate: '2026-07-04',
+    earliestDate: '2026-06-04',
+  } as const;
+  const currentRows = {
+    [Model.Qwen3_5]: [
+      ...frontier([12000, 10000, 8000, 6000], {
+        hardware: 'mi355x',
+        framework: 'sglang',
+        date: '2026-08-01',
+        precision: Precision.FP4,
+      }),
+      ...frontier([9600, 8000, 6400, 4800], {
+        hardware: 'b300',
+        framework: 'sglang',
+        date: '2026-08-02',
+        precision: Precision.FP4,
+      }),
+      ...frontier([8400, 7000, 5600, 4200], {
+        hardware: 'gb200',
+        framework: 'sglang',
+        date: '2026-07-04',
+        precision: Precision.FP4,
+      }),
+    ],
+  };
+  const baselineRows = {
+    [Model.Qwen3_5]: [
+      ...frontier([9600, 8000, 6400, 4800], {
+        hardware: 'mi355x',
+        framework: 'vllm',
+        date: '2026-06-20',
+        precision: Precision.FP4,
+      }),
+      ...frontier([8400, 7000, 5600, 4200], {
+        hardware: 'gb200',
+        framework: 'sglang',
+        date: '2026-06-20',
+        precision: Precision.FP4,
+      }),
+    ],
+  };
+
+  it('compares each current platform envelope with the same historical platform', () => {
+    const page = assembleOverviewHistoricalPageData(
+      currentRows,
+      baselineRows,
+      window,
+      50,
+      'community',
+    );
+    const platform = platformFor(page, Model.Qwen3_5, 'single_turn_8k1k', 'mi355x');
+
+    expect(page.comparisonMode).toBe('history');
+    expect(page.historicalWindow).toEqual(window);
+    expect(platform?.historicalComparison?.status).toBe('comparable');
+    expect(platform?.historicalComparison?.costDeltaPct).toBeCloseTo(-0.2, 9);
+    expect(platform?.historicalComparison?.baselineDate).toBe('2026-06-20');
+  });
+
+  it('marks a priced current cell without a baseline as no_baseline', () => {
+    const page = assembleOverviewHistoricalPageData(
+      currentRows,
+      baselineRows,
+      window,
+      50,
+      'community',
+    );
+    const comparison = platformFor(
+      page,
+      Model.Qwen3_5,
+      'single_turn_8k1k',
+      'b300',
+    )?.historicalComparison;
+
+    expect(comparison).toEqual({
+      status: 'no_baseline',
+      baselineCostPerMtok: null,
+      costDeltaPct: null,
+      baselineDate: null,
+    });
+  });
+
+  it('does not report zero improvement when current evidence is not newer than the cutoff', () => {
+    const page = assembleOverviewHistoricalPageData(
+      currentRows,
+      baselineRows,
+      window,
+      50,
+      'community',
+    );
+    const comparison = platformFor(
+      page,
+      Model.Qwen3_5,
+      'single_turn_8k1k',
+      'gb200',
+    )?.historicalComparison;
+
+    expect(comparison?.status).toBe('no_newer_result');
+    expect(comparison?.costDeltaPct).toBeNull();
+  });
+
+  it('allows the winning engine to change between snapshots', () => {
+    const page = assembleOverviewHistoricalPageData(
+      currentRows,
+      baselineRows,
+      window,
+      50,
+      'community',
+    );
+    const current = platformFor(page, Model.Qwen3_5, 'single_turn_8k1k', 'mi355x');
+    const baseline = buildOverviewModelSummary(
+      Model.Qwen3_5,
+      baselineRows[Model.Qwen3_5],
+      50,
+      'community',
+      'single_turn_8k1k',
+    ).platforms.find((platform) => platform.hardware === 'mi355x');
+
+    expect(current?.read.config?.framework).toBe('sglang');
+    expect(baseline?.read.config?.framework).toBe('vllm');
+    expect(current?.historicalComparison?.status).toBe('comparable');
+  });
+});
+
 describe('overview platform selection', () => {
   it('keeps FP4 platform boundaries when neither side has an exact read', () => {
     const summary = buildOverviewModelSummary(Model.Qwen3_5, [
diff --git a/packages/app/src/lib/overview-data.ts b/packages/app/src/lib/overview-data.ts
index 9e474025..9f6c95d2 100644
--- a/packages/app/src/lib/overview-data.ts
+++ b/packages/app/src/lib/overview-data.ts
@@ -20,6 +20,8 @@ export const OVERVIEW_TIERS = [30, 50, 75, 100, 150, 200] as const;
 export type OverviewTier = (typeof OVERVIEW_TIERS)[number];
 export const OVERVIEW_PRIMARY_TIER = 50;
 export type OverviewEngineScope = 'all' | 'community';
+export type OverviewComparisonMode = 'hardware' | 'history';
+export const OVERVIEW_DEFAULT_COMPARISON_MODE: OverviewComparisonMode = 'hardware';
 export type OverviewScenario = 'single_turn_8k1k' | 'agentx';
 /** Row order within a model: the single-turn workload first, AgentX below it. */
 export const OVERVIEW_SCENARIOS = ['single_turn_8k1k', 'agentx'] as const;
@@ -31,6 +33,13 @@ export function resolveOverviewEngineScope(
   return candidate === 'all' ? 'all' : 'community';
 }
 
+export function resolveOverviewComparisonMode(
+  raw: string | readonly string[] | undefined,
+): OverviewComparisonMode {
+  const candidate = Array.isArray(raw) ? raw[0] : raw;
+  return candidate === '30d' ? 'history' : OVERVIEW_DEFAULT_COMPARISON_MODE;
+}
+
 export function resolveOverviewTier(raw: string | string[] | undefined): OverviewTier {
   const candidate = Number(Array.isArray(raw) ? raw[0] : raw);
   return OVERVIEW_TIERS.find((tier) => tier === candidate) ?? OVERVIEW_PRIMARY_TIER;
@@ -89,6 +98,15 @@ export type OverviewMissingReason =
   | 'cannot_reach_at_tier'
   | 'no_exact_at_tier';
 
+export type OverviewHistoricalStatus = 'comparable' | 'no_baseline' | 'no_newer_result';
+
+export interface OverviewHistoricalComparison {
+  status: OverviewHistoricalStatus;
+  baselineCostPerMtok: number | null;
+  costDeltaPct: number | null;
+  baselineDate: string | null;
+}
+
 export const OVERVIEW_HARDWARE = ['b200', 'mi355x', 'b300', 'gb200', 'gb300'] as const;
 
 export interface OverviewPlatformResult {
@@ -103,6 +121,7 @@ export interface OverviewPlatformResult {
   /** Cost delta vs this row's B200 cell; negative = cheaper. Null on the B200
    *  cell itself and whenever either cost is unavailable. */
   costVsB200Pct: number | null;
+  historicalComparison: OverviewHistoricalComparison | null;
 }
 
 export interface OverviewModelSummary {
@@ -116,6 +135,60 @@ export interface OverviewPageData {
   models: OverviewModelSummary[];
   tier: OverviewTier;
   engineScope: OverviewEngineScope;
+  comparisonMode: OverviewComparisonMode;
+  historicalWindow: OverviewHistoricalWindow | null;
+}
+
+export interface OverviewHistoricalWindow {
+  snapshotDate: string;
+  targetDate: string;
+  earliestDate: string;
+}
+
+function overviewScenarioOfRow(row: BenchmarkRow): OverviewScenario | null {
+  if (row.benchmark_type === 'agentic_traces') return 'agentx';
+  if (
+    row.benchmark_type === 'single_turn' &&
+    row.isl === OVERVIEW_WORKLOAD.isl &&
+    row.osl === OVERVIEW_WORKLOAD.osl
+  ) {
+    return 'single_turn_8k1k';
+  }
+  return null;
+}
+
+function subtractUtcDays(isoDate: string, days: number): string {
+  const date = new Date(`${isoDate}T00:00:00Z`);
+  date.setUTCDate(date.getUTCDate() - days);
+  return date.toISOString().slice(0, 10);
+}
+
+export function overviewSnapshotDate(
+  rowsByModel: Readonly<Record<string, readonly BenchmarkRow[]>>,
+  engineScope: OverviewEngineScope = 'community',
+): string | null {
+  const dates = Object.entries(rowsByModel).flatMap(([modelKey, rows]) => {
+    const scenarios = overviewScenariosForModel(modelKey as Model, rows);
+    return overviewEngineRows(rows, engineScope)
+      .filter((row) => {
+        const scenario = overviewScenarioOfRow(row);
+        return (
+          (OVERVIEW_HARDWARE as readonly string[]).includes(row.hardware) &&
+          scenario !== null &&
+          scenarios.includes(scenario)
+        );
+      })
+      .map((row) => row.date);
+  });
+  return dates.length === 0 ? null : (dates.toSorted().at(-1) ?? null);
+}
+
+export function overviewHistoricalWindow(snapshotDate: string): OverviewHistoricalWindow {
+  return {
+    snapshotDate,
+    targetDate: subtractUtcDays(snapshotDate, 30),
+    earliestDate: subtractUtcDays(snapshotDate, 60),
+  };
 }
 
 const OVERVIEW_SLICE_PRIORITY = [
@@ -269,8 +342,12 @@ interface ConfigTierRead extends OverviewTierRead {
 const isInRangeTierRead = <T extends OverviewTierRead>(read: T): read is T & { value: number } =>
   read.value !== null && read.boundary === 'interpolated';
 
+export function overviewTierEvidenceDate(read: OverviewTierRead): string | null {
+  return read.evidenceDate?.to ?? read.config?.latestDate ?? null;
+}
+
 function readFreshness(read: ConfigTierRead): string {
-  return read.evidenceDate?.to ?? read.config.latestDate;
+  return overviewTierEvidenceDate(read) ?? read.config.latestDate;
 }
 
 function compareTierReads(a: ConfigTierRead, b: ConfigTierRead): number {
@@ -416,6 +493,7 @@ function buildPlatformResults(
       platform.hardware === 'b200' || b200Cost === null || platform.costPerMtok === null
         ? null
         : platform.costPerMtok / b200Cost - 1,
+    historicalComparison: null,
   }));
 }
 
@@ -571,5 +649,78 @@ export function assembleOverviewPageData(
     ),
     tier,
     engineScope,
+    comparisonMode: OVERVIEW_DEFAULT_COMPARISON_MODE,
+    historicalWindow: null,
+  };
+}
+
+function overviewPlatformKey(
+  model: OverviewModelSummary,
+  platform: OverviewPlatformResult,
+): string {
+  return `${model.model}|${model.scenario}|${platform.hardware}`;
+}
+
+export function assembleOverviewHistoricalPageData(
+  currentRowsByModel: Record<string, BenchmarkRow[]>,
+  baselineRowsByModel: Record<string, BenchmarkRow[]>,
+  window: OverviewHistoricalWindow,
+  tier: OverviewTier = OVERVIEW_PRIMARY_TIER,
+  engineScope: OverviewEngineScope = 'community',
+): OverviewPageData {
+  const current = assembleOverviewPageData(currentRowsByModel, tier, engineScope);
+  const baseline = assembleOverviewPageData(baselineRowsByModel, tier, engineScope);
+  const baselineByKey = new Map(
+    baseline.models.flatMap((model) =>
+      model.platforms.map((platform) => [overviewPlatformKey(model, platform), platform] as const),
+    ),
+  );
+
+  return {
+    ...current,
+    comparisonMode: 'history',
+    historicalWindow: window,
+    models: current.models.map((model) => ({
+      ...model,
+      platforms: model.platforms.map((platform) => {
+        if (platform.costPerMtok === null) return platform;
+
+        const previous = baselineByKey.get(overviewPlatformKey(model, platform));
+        const currentDate = overviewTierEvidenceDate(platform.read);
+        if (currentDate === null || currentDate <= window.targetDate) {
+          return {
+            ...platform,
+            historicalComparison: {
+              status: 'no_newer_result',
+              baselineCostPerMtok: previous?.costPerMtok ?? null,
+              costDeltaPct: null,
+              baselineDate: previous === undefined ? null : overviewTierEvidenceDate(previous.read),
+            },
+          };
+        }
+
+        if (previous === undefined || previous.costPerMtok === null) {
+          return {
+            ...platform,
+            historicalComparison: {
+              status: 'no_baseline',
+              baselineCostPerMtok: null,
+              costDeltaPct: null,
+              baselineDate: null,
+            },
+          };
+        }
+
+        return {
+          ...platform,
+          historicalComparison: {
+            status: 'comparable',
+            baselineCostPerMtok: previous.costPerMtok,
+            costDeltaPct: platform.costPerMtok / previous.costPerMtok - 1,
+            baselineDate: overviewTierEvidenceDate(previous.read),
+          },
+        };
+      }),
+    })),
   };
 }
diff --git a/packages/app/src/lib/overview-links.test.ts b/packages/app/src/lib/overview-links.test.ts
index 55a8fb75..9cb8c5f6 100644
--- a/packages/app/src/lib/overview-links.test.ts
+++ b/packages/app/src/lib/overview-links.test.ts
@@ -169,6 +169,17 @@ describe('overviewHref', () => {
     expect(overviewHref('en', 50, 'community')).toBe('/overview');
     expect(overviewHref('en', 30, 'all')).toBe('/overview?tier=30&engine=all');
   });
+
+  it('adds historical comparison last and omits the default comparison mode', () => {
+    expect(overviewHref('en', 50, 'community', 'hardware')).toBe('/overview');
+    expect(overviewHref('en', 50, 'community', 'history')).toBe('/overview?compare=30d');
+    expect(overviewHref('en', 100, 'all', 'history')).toBe(
+      '/overview?tier=100&engine=all&compare=30d',
+    );
+    expect(overviewHref('zh', 100, 'all', 'history')).toBe(
+      '/zh/overview?tier=100&engine=all&compare=30d',
+    );
+  });
 });
 
 describe('overview switch links', () => {
@@ -185,6 +196,12 @@ describe('overview switch links', () => {
     },
   );
 
+  it('preserves historical comparison when changing tiers', () => {
+    expect(overviewTierHref('en', 75, 'all', 'history')).toBe(
+      '/overview?tier=75&engine=all&compare=30d',
+    );
+  });
+
   it.each([
     ['en', 'all', 50, '/overview?engine=all'],
     ['en', 'all', 100, '/overview?tier=100&engine=all'],
@@ -197,4 +214,10 @@ describe('overview switch links', () => {
       ).toBe(expected);
     },
   );
+
+  it('preserves historical comparison when changing engine scope', () => {
+    expect(overviewEngineScopeHref('en', 'all', 50, 'history')).toBe(
+      '/overview?engine=all&compare=30d',
+    );
+  });
 });
diff --git a/packages/app/src/lib/overview-links.ts b/packages/app/src/lib/overview-links.ts
index d7aa8d5a..1463cac5 100644
--- a/packages/app/src/lib/overview-links.ts
+++ b/packages/app/src/lib/overview-links.ts
@@ -1,6 +1,8 @@
 import { runIdFromRunUrl } from './known-issues';
 import {
+  OVERVIEW_DEFAULT_COMPARISON_MODE,
   OVERVIEW_PRIMARY_TIER,
+  type OverviewComparisonMode,
   type OverviewConfigResult,
   type OverviewEngineScope,
   type OverviewModelSummary,
@@ -94,11 +96,13 @@ export function overviewHref(
   locale: 'en' | 'zh',
   tier: OverviewTier = OVERVIEW_PRIMARY_TIER,
   engineScope: OverviewEngineScope = 'community',
+  comparisonMode: OverviewComparisonMode = OVERVIEW_DEFAULT_COMPARISON_MODE,
 ): string {
   const base = locale === 'zh' ? '/zh/overview' : '/overview';
   const query = new URLSearchParams();
   if (tier !== OVERVIEW_PRIMARY_TIER) query.set('tier', String(tier));
   if (engineScope !== 'community') query.set('engine', engineScope);
+  if (comparisonMode === 'history') query.set('compare', '30d');
   const search = query.toString();
   return search === '' ? base : `${base}?${search}`;
 }
@@ -108,8 +112,9 @@ export function overviewTierHref(
   locale: 'en' | 'zh',
   tier: OverviewTier,
   engineScope: OverviewEngineScope = 'community',
+  comparisonMode: OverviewComparisonMode = OVERVIEW_DEFAULT_COMPARISON_MODE,
 ): string {
-  return overviewHref(locale, tier, engineScope);
+  return overviewHref(locale, tier, engineScope, comparisonMode);
 }
 
 /** Engine-scope switch preserving the active service tier. */
@@ -117,6 +122,7 @@ export function overviewEngineScopeHref(
   locale: 'en' | 'zh',
   engineScope: OverviewEngineScope,
   tier: OverviewTier = OVERVIEW_PRIMARY_TIER,
+  comparisonMode: OverviewComparisonMode = OVERVIEW_DEFAULT_COMPARISON_MODE,
 ): string {
-  return overviewHref(locale, tier, engineScope);
+  return overviewHref(locale, tier, engineScope, comparisonMode);
 }
diff --git a/packages/db/src/etl/trace-replay-ingest.test.ts b/packages/db/src/etl/trace-replay-ingest.test.ts
index a77d87aa..5cef23f0 100644
--- a/packages/db/src/etl/trace-replay-ingest.test.ts
+++ b/packages/db/src/etl/trace-replay-ingest.test.ts
@@ -119,7 +119,7 @@ describe('gzipTraceReplayInput', () => {
     } finally {
       await rm(dir, { recursive: true, force: true });
     }
-  });
+  }, 15_000);
 });
 
 describe('persistPreparedTraceReplay', () => {