diff --git a/.github/workflows/wasm-build.yml b/.github/workflows/wasm-build.yml
index 4de7685..46847a4 100644
--- a/.github/workflows/wasm-build.yml
+++ b/.github/workflows/wasm-build.yml
@@ -304,6 +304,16 @@ jobs:
         working-directory: tests
         run: xvfb-run -a npm run test:kicad:ci
 
+      # Runtime-perf E2E (eeschema + pcbnew): measures the current build's
+      # load / open+render / FPS and writes tests/test-results/perf-*.json.
+      # Track-only — never gates the build (continue-on-error). CI is
+      # headless/SwiftShader so FPS is CPU-bound + noisy; openMs is the stable number.
+      - name: KiCad runtime perf (track-only, non-gating)
+        if: inputs.run_tests
+        continue-on-error: true
+        working-directory: tests
+        run: xvfb-run -a npm run test:perf
+
       - name: Upload test logs & screenshots
         if: always() && inputs.run_tests
         uses: actions/upload-artifact@v4
diff --git a/.gitignore b/.gitignore
index e1511fb..3cc561f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -83,6 +83,11 @@ output/
 /bench/
 /scripts/bench/vm/
 
+# Temporary/disposable prebuilt WASM sets (native-EH + JS-EH × eeschema + pcbnew
+# O1 builds) + the standalone perf harness, used to reproduce the runtime-perf
+# comparison on demand. Large (~1 GB), never committed.
+/benchmark-builds/
+
 /tests/.test-port-asyncify
 /memory/
 
diff --git a/tests/kicad/eeschema-perf.spec.ts b/tests/kicad/eeschema-perf.spec.ts
new file mode 100644
index 0000000..acfd463
--- /dev/null
+++ b/tests/kicad/eeschema-perf.spec.ts
@@ -0,0 +1,47 @@
+import { test, expect } from './fixtures';
+import * as path from 'path';
+import { measureLoad, measureOpenRender, measureFps, setThrottle, recordPerf } from './utils/perf-utils';
+
+/**
+ * eeschema runtime-perf (TRACK-ONLY, no gating).
+ *
+ * Measures the CURRENT build: cold load, open+render of the demo schematic, and
+ * sustained pan/zoom FPS across CPU-throttle rates. Numbers are logged and written
+ * to tests/test-results/perf-eeschema.json (CI uploads it). The only assertions are
+ * "the app booted and the doc opened" — never a perf threshold (would flake CI).
+ * Runs on the Chromium 'perf' project (CDP throttling); pass --headed for real-GPU FPS.
+ * Note: on headless/SwiftShader CI, FPS is CPU-bound and noisy — openMs is the stable metric.
+ */
+
+const THROTTLES = (process.env.PERF_THROTTLES || '1,4,6').split(',').map(Number);
+const FPS_SECS = parseInt(process.env.PERF_FPS_SECS || '6', 10);
+const DEMO = path.join(__dirname, '..', 'fixtures', 'demo', 'demo.kicad_sch');
+
+test.describe('eeschema perf', () => {
+    test('load + open+render + FPS (track-only)', async ({ page, testLogger }) => {
+        test.setTimeout(300000);
+
+        const loadMs = await measureLoad(page, '/kicad/eeschema.html');
+        console.log(`[perf] eeschema cold load = ${loadMs} ms`);
+
+        const openMs = await measureOpenRender(page, DEMO, 'schematic', testLogger);
+        console.log(`[perf] eeschema open+render = ${openMs} ms`);
+        await page.keyboard.press('Escape').catch(() => {});
+
+        const cdp = await page.context().newCDPSession(page);
+        const fps: { throttle: number; fps: number }[] = [];
+        for (const rate of THROTTLES) {
+            await setThrottle(cdp, rate);
+            const f = await measureFps(page, FPS_SECS);
+            console.log(`[perf] eeschema FPS @ ${rate}x = ${f}`);
+            fps.push({ throttle: rate, fps: f });
+        }
+        await setThrottle(cdp, 1);
+
+        recordPerf('eeschema', { loadMs, openMs, fps });
+
+        // Track-only: assert only that it booted + opened.
+        expect(loadMs).toBeGreaterThan(0);
+        expect(openMs).toBeGreaterThan(0);
+    });
+});
diff --git a/tests/kicad/pcbnew-perf.spec.ts b/tests/kicad/pcbnew-perf.spec.ts
new file mode 100644
index 0000000..d8f2649
--- /dev/null
+++ b/tests/kicad/pcbnew-perf.spec.ts
@@ -0,0 +1,44 @@
+import { test, expect } from './fixtures';
+import * as path from 'path';
+import { measureLoad, measureOpenRender, measureFps, setThrottle, recordPerf } from './utils/perf-utils';
+
+/**
+ * pcbnew runtime-perf (TRACK-ONLY, no gating). Mirrors eeschema-perf for the board editor.
+ *
+ * Measures the CURRENT build: cold load, open+render of the demo board, and sustained
+ * pan/zoom FPS across CPU-throttle rates → tests/test-results/perf-pcbnew.json (CI uploads it).
+ * Runs on the Chromium 'perf' project (pcbnew's big module OOMs Firefox/SpiderMonkey anyway,
+ * and CDP throttling is Chromium-only). Only asserts booted + opened; never a perf threshold.
+ */
+
+const THROTTLES = (process.env.PERF_THROTTLES || '1,4,6').split(',').map(Number);
+const FPS_SECS = parseInt(process.env.PERF_FPS_SECS || '6', 10);
+const DEMO = path.join(__dirname, '..', 'fixtures', 'demo', 'demo.kicad_pcb');
+
+test.describe('pcbnew perf', () => {
+    test('load + open+render + FPS (track-only)', async ({ page, testLogger }) => {
+        test.setTimeout(300000);
+
+        const loadMs = await measureLoad(page, '/kicad/pcbnew.html');
+        console.log(`[perf] pcbnew cold load = ${loadMs} ms`);
+
+        const openMs = await measureOpenRender(page, DEMO, 'board', testLogger);
+        console.log(`[perf] pcbnew open+render = ${openMs} ms`);
+        await page.keyboard.press('Escape').catch(() => {});
+
+        const cdp = await page.context().newCDPSession(page);
+        const fps: { throttle: number; fps: number }[] = [];
+        for (const rate of THROTTLES) {
+            await setThrottle(cdp, rate);
+            const f = await measureFps(page, FPS_SECS);
+            console.log(`[perf] pcbnew FPS @ ${rate}x = ${f}`);
+            fps.push({ throttle: rate, fps: f });
+        }
+        await setThrottle(cdp, 1);
+
+        recordPerf('pcbnew', { loadMs, openMs, fps });
+
+        expect(loadMs).toBeGreaterThan(0);
+        expect(openMs).toBeGreaterThan(0);
+    });
+});
diff --git a/tests/kicad/utils/perf-utils.ts b/tests/kicad/utils/perf-utils.ts
new file mode 100644
index 0000000..1283dd3
--- /dev/null
+++ b/tests/kicad/utils/perf-utils.ts
@@ -0,0 +1,138 @@
+import * as fs from 'fs';
+import * as path from 'path';
+import type { Page, CDPSession } from '@playwright/test';
+import { injectFileIntoMemfs } from './fs-inject';
+import { waitForBoardLoaded } from './board-ready';
+
+/**
+ * Runtime-perf helpers for the track-only perf specs (eeschema-perf, pcbnew-perf).
+ *
+ * Measures the CURRENT build (whatever setup:kicad staged into tests/apps/kicad/):
+ * cold load, open+render time, and interaction FPS. No version A/B, no gating —
+ * results are logged and written to tests/test-results/perf-<app>.json (gitignored,
+ * uploaded by CI). The measurement logic (the #canvas real-input FPS driver, the
+ * ready-signal, CDP throttling) is lifted from the validated native-vs-JS-EH
+ * benchmark harness — see docs/features/wasm-exceptions/12-native-vs-jseh-benchmark.md.
+ */
+
+const MAIN_CANVAS = '#canvas';
+const RESULTS_DIR = path.join(__dirname, '..', '..', 'test-results');
+
+type KicadModule = { kicadOpenFile(p: string): unknown };
+
+/** Fully booted editor: visible canvas + wx registry + kicadOpenFile hook + a top-level *Frame. */
+export async function waitForReady(page: Page, timeout = 120000): Promise<void> {
+    await page.locator(MAIN_CANVAS).waitFor({ state: 'visible', timeout });
+    await page.waitForFunction(() => !!window.wxElementRegistry, null, { timeout });
+    await page.waitForFunction(
+        () =>
+            typeof (window as unknown as { Module?: KicadModule }).Module?.kicadOpenFile === 'function',
+        null,
+        { timeout },
+    );
+    await page.waitForFunction(
+        () =>
+            !!window.wxElementRegistry &&
+            window.wxElementRegistry
+                .findAll({ visible: true })
+                .some((e) => /Frame$/.test(e.typeName) || (e.name || '').endsWith('Frame')),
+        null,
+        { timeout },
+    );
+}
+
+/** Cold load: navigate then wait until fully ready. Returns ms. */
+export async function measureLoad(page: Page, url: string, timeout = 120000): Promise<number> {
+    const t0 = Date.now();
+    await page.goto(url, { waitUntil: 'commit', timeout });
+    await waitForReady(page, timeout);
+    return Date.now() - t0;
+}
+
+/**
+ * Open a document via Module.kicadOpenFile and wait until it's loaded+rendered.
+ * 'schematic' polls the editor title; 'board' uses the pcbnew progress-dialog signal.
+ * Returns ms.
+ */
+export async function measureOpenRender(
+    page: Page,
+    hostPath: string,
+    kind: 'schematic' | 'board',
+    logger: { consoleLogs: string[]; errors: string[] },
+    timeout = 120000,
+): Promise<number> {
+    const ext = kind === 'board' ? 'kicad_pcb' : 'kicad_sch';
+    const memfsPath = `/home/kicad/documents/perf-demo.${ext}`;
+    await injectFileIntoMemfs(page, hostPath, memfsPath);
+
+    const t0 = Date.now();
+    await page.evaluate((p) => {
+        (window as unknown as { Module: KicadModule }).Module.kicadOpenFile(p);
+    }, memfsPath);
+
+    if (kind === 'board') {
+        await waitForBoardLoaded(page, logger, timeout);
+    } else {
+        const deadline = Date.now() + timeout;
+        while (Date.now() < deadline) {
+            if (/perf-demo/i.test(await page.title())) break;
+            await page.waitForTimeout(200);
+        }
+    }
+    return Date.now() - t0;
+}
+
+/** CDP CPU throttling (Chromium only): 1 = none, N = N× slower. */
+export async function setThrottle(cdp: CDPSession, rate: number): Promise<void> {
+    await cdp.send('Emulation.setCPUThrottlingRate', { rate });
+}
+
+/**
+ * Sustained interaction FPS: drive real pan/zoom on #canvas (the emscripten input
+ * surface — glcanvas-* can be display:none) for `seconds`, counting main-thread rAF
+ * frames. Whatever throttle is currently set applies.
+ */
+export async function measureFps(page: Page, seconds: number): Promise<number> {
+    const box = await page.locator(MAIN_CANVAS).boundingBox();
+    if (!box) return 0;
+    type W = { __perfFrames: number; __perfRAF?: number };
+    // Start ONE rAF frame counter, cancelling any loop left over from a prior call
+    // (otherwise loops accumulate across a throttle sweep and inflate the count).
+    await page.evaluate(() => {
+        const w = window as unknown as W;
+        if (w.__perfRAF !== undefined) cancelAnimationFrame(w.__perfRAF);
+        w.__perfFrames = 0;
+        const loop = () => {
+            w.__perfFrames++;
+            w.__perfRAF = requestAnimationFrame(loop);
+        };
+        w.__perfRAF = requestAnimationFrame(loop);
+    });
+    const cx = box.x + box.width / 2;
+    const cy = box.y + box.height / 2;
+    const start = Date.now();
+    let k = 0;
+    await page.mouse.move(cx, cy);
+    while (Date.now() - start < seconds * 1000) {
+        await page.mouse.move(cx + Math.round(120 * Math.sin(k / 3)), cy + Math.round(80 * Math.cos(k / 4)));
+        if (k % 3 === 0) await page.mouse.wheel(0, k % 6 < 3 ? -120 : 120);
+        k++;
+    }
+    const elapsed = Date.now() - start;
+    const frames = await page.evaluate(() => {
+        const w = window as unknown as W;
+        if (w.__perfRAF !== undefined) cancelAnimationFrame(w.__perfRAF);
+        return w.__perfFrames;
+    });
+    return +(frames / (elapsed / 1000)).toFixed(1);
+}
+
+/** Write per-app results to tests/test-results/perf-<app>.json (gitignored, CI-uploaded). */
+export function recordPerf(app: string, data: Record<string, unknown>): void {
+    fs.mkdirSync(RESULTS_DIR, { recursive: true });
+    const out = { app, when: new Date().toISOString(), ...data };
+    fs.writeFileSync(path.join(RESULTS_DIR, `perf-${app}.json`), JSON.stringify(out, null, 2));
+    // Also echo a compact line so it lands in the captured test log / CI output.
+    // eslint-disable-next-line no-console
+    console.log(`[perf] ${app}: ${JSON.stringify(data)}`);
+}
diff --git a/tests/package.json b/tests/package.json
index 918fb5b..1638324 100644
--- a/tests/package.json
+++ b/tests/package.json
@@ -18,6 +18,7 @@
     "test:kicad": "npm run test:kicad:firefox",
     "test:kicad:ci": "npm run setup:kicad && playwright test --config=playwright-kicad.config.ts --project=firefox --project=chromium-ci",
     "test:kicad:headed": "npm run test:kicad:chrome",
+    "test:perf": "npm run setup:kicad && playwright test --config=playwright-kicad.config.ts --project=perf --workers=1",
     "test:pcbnew:firefox": "npm run setup:kicad && playwright test --config=playwright-kicad.config.ts --project=firefox kicad/pcbnew.spec.ts",
     "test:pcbnew:chrome": "npm run setup:kicad && playwright test --config=playwright-kicad.config.ts --project=chromium --headed kicad/pcbnew.spec.ts",
     "test:eeschema:firefox": "npm run setup:kicad && playwright test --config=playwright-kicad.config.ts --project=firefox kicad/eeschema.spec.ts",
diff --git a/tests/playwright-kicad.config.ts b/tests/playwright-kicad.config.ts
index 058f3a3..7da34c7 100644
--- a/tests/playwright-kicad.config.ts
+++ b/tests/playwright-kicad.config.ts
@@ -92,6 +92,11 @@ const PCBNEW_FAMILY_SPECS = [
   '**/footprint-3d-preview.spec.ts',
 ];
 
+// Runtime-perf specs run ONLY on the Chromium 'perf' project below: they need
+// CDP CPU throttling (Chromium-only) and pcbnew needs V8. Excluded from the
+// firefox/chromium projects so they don't double-run there.
+const PERF_SPECS = ['**/*-perf.spec.ts'];
+
 const appsDir = 'apps';
 
 export default defineConfig({
@@ -120,9 +125,9 @@ export default defineConfig({
     {
       // Firefox is the default for headless testing (works on ARM Mac)
       name: 'firefox',
-      // On CI the pcbnew-family specs run on chromium-ci instead (see
-      // PCBNEW_FAMILY_SPECS above for why).
-      ...(process.env.CI ? { testIgnore: PCBNEW_FAMILY_SPECS } : {}),
+      // Perf specs always run on the dedicated 'perf' project, never here. On CI
+      // the pcbnew-family specs also move to chromium-ci (see PCBNEW_FAMILY_SPECS).
+      testIgnore: [...PERF_SPECS, ...(process.env.CI ? PCBNEW_FAMILY_SPECS : [])],
       use: {
         ...devices['Desktop Firefox'],
         viewport: { width: 1280, height: 720 },
@@ -157,6 +162,7 @@ export default defineConfig({
       // Chromium issues #1416283, #338414704 (SwiftShader WebGL bug).
       // Run via: npm run test:kicad:headed
       name: 'chromium',
+      testIgnore: PERF_SPECS,
       use: {
         channel: 'chrome',
         viewport: { width: 1280, height: 720 },
@@ -178,6 +184,20 @@ export default defineConfig({
         },
       },
     },
+    {
+      // Runtime-perf specs (*-perf.spec.ts): bundled Chromium for CDP CPU throttling.
+      // Bundled (not system Chrome) because system Chrome paces rAF oddly under CDP
+      // throttle (FPS rose with throttle). --enable-unsafe-swiftshader lets it use
+      // software WebGL headless on CI; harmless with a real GPU locally. Add --headed
+      // locally for real-GPU FPS numbers.
+      name: 'perf',
+      testMatch: PERF_SPECS,
+      use: {
+        ...devices['Desktop Chrome'],
+        viewport: { width: 1280, height: 720 },
+        launchOptions: { args: ['--enable-unsafe-swiftshader'] },
+      },
+    },
   ],
 
   webServer: {