diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 58c18ae68d7..2a612c5b922 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -1301,9 +1301,10 @@ jobs:
       # vitest runs here directly rather than through `pnpm test`, so the addon
       # assertions only hold once install-node-dependencies has rebuilt natives.
       - name: Test Windows installer process probe
-        # Keep cold CIM startup out of the concurrent Electron/native process workload.
+        # Serialize the two suites so their cold PowerShell/CIM starts cannot contend.
         run: >-
           pnpm exec vitest run --config config/vitest.config.ts
+          --no-file-parallelism
           config/scripts/nsis-process-check.test.mjs
           config/scripts/idle-cpu-process-sampling.test.mjs
 
diff --git a/config/scripts/ci-shard-assignment.test.mjs b/config/scripts/ci-shard-assignment.test.mjs
index 3baedc084e9..a2c4729cade 100644
--- a/config/scripts/ci-shard-assignment.test.mjs
+++ b/config/scripts/ci-shard-assignment.test.mjs
@@ -63,7 +63,7 @@ describe('timing-weighted shard selection', () => {
     expect(new Set(selected)).toEqual(new Set(specs))
   })
 
-  it('keeps global sharding and runs the Node measurement after ordinary projects', async () => {
+  it('keeps global sharding and isolates measurements after ordinary projects', async () => {
     vi.stubEnv('ORCA_BALANCE_UNIT_SHARDS', '1')
     const { default: config } = await import('../vitest.config')
     expect(config.test.sequence.sequencer).toBe(TimingSequencer)
@@ -72,7 +72,12 @@ describe('timing-weighted shard selection', () => {
       'src/main/foreign-sqlite-readers/foreign-sqlite-reader-event-loop.test.ts'
     const projects = config.test.projects
     const measurement = projects.filter((project) => project.test.name === 'node-measurement')
-    const ordinary = projects.filter((project) => project.test.name !== 'node-measurement')
+    const paletteMeasurementFile =
+      'src/renderer/src/lib/palette-match/palette-match-performance.test.ts'
+    const paletteMeasurement = projects.filter(
+      (project) => project.test.name === 'palette-measurement'
+    )
+    const ordinary = projects.filter((project) => project.test.sequence.groupOrder === 1)
     expect(measurement).toHaveLength(1)
     expect(ordinary).toHaveLength(process.versions.bun ? 2 : 1)
     expect(measurement[0].test).toMatchObject({
@@ -84,9 +89,21 @@ describe('timing-weighted shard selection', () => {
       pool: process.versions.bun ? 'node-runtime' : 'forks'
     })
     expect(measurement[0].test.poolRunner).toBe(process.versions.bun ? nodeRuntimePool : undefined)
+    expect(paletteMeasurement).toHaveLength(1)
+    expect(paletteMeasurement[0].test).toMatchObject({
+      include: [paletteMeasurementFile],
+      exclude: UNIT_EXCLUDE,
+      maxWorkers: 1,
+      sequence: { groupOrder: 3 },
+      env: { ORCA_VITEST_RUNTIME: process.versions.bun ? 'bun' : 'node' },
+      pool: 'forks'
+    })
+    expect(paletteMeasurement[0].test.poolRunner).toBeUndefined()
     for (const project of ordinary) {
       expect(project.test.sequence.groupOrder).toBe(1)
-      expect(project.test.exclude).toContain(measurementFile)
+      expect(project.test.exclude).toEqual(
+        expect.arrayContaining([measurementFile, paletteMeasurementFile])
+      )
     }
     const ordinaryNode = ordinary.find((project) => project.test.name !== 'bun')
     expect(ordinaryNode.test.include).toEqual(
diff --git a/config/vitest.config.ts b/config/vitest.config.ts
index eab4441b407..6af92217a6e 100644
--- a/config/vitest.config.ts
+++ b/config/vitest.config.ts
@@ -9,6 +9,9 @@ import { createWorkspaceSourceResolver } from './scripts/workspace-source-export
 
 const balancedShards = process.env.ORCA_BALANCE_UNIT_SHARDS === '1'
 const measurementFile = 'src/main/foreign-sqlite-readers/foreign-sqlite-reader-event-loop.test.ts'
+const paletteMeasurementFile =
+  'src/renderer/src/lib/palette-match/palette-match-performance.test.ts'
+const measurementFiles = [measurementFile, paletteMeasurementFile]
 const transforms = {
   define: {
     ORCA_FEATURE_WALL_ENABLED: 'true',
@@ -59,30 +62,28 @@ const nodeProject = {
     name: process.versions.bun ? 'node-runtime' : 'node',
     env: { ORCA_VITEST_RUNTIME: process.versions.bun ? 'node-runtime' : 'node' },
     include: process.versions.bun ? NODE_RUNTIME_INCLUDE : UNIT_INCLUDE,
-    exclude: [...testOptions.exclude, measurementFile],
+    exclude: [...testOptions.exclude, ...measurementFiles],
     sequence: { groupOrder: 1 },
     ...(process.versions.bun
       ? { pool: 'node-runtime', poolRunner: nodeRuntimePool }
       : { pool: 'forks' })
   }
 }
+const bunProject = {
+  extends: false,
+  ...transforms,
+  test: {
+    ...testOptions,
+    name: 'bun',
+    env: { ORCA_VITEST_RUNTIME: 'bun' },
+    pool: 'forks',
+    exclude: [...testOptions.exclude, ...NODE_RUNTIME_INCLUDE, ...measurementFiles],
+    sequence: { groupOrder: 1 }
+  }
+}
+const paletteRuntimeProject = process.versions.bun ? bunProject : nodeProject
 const projects = [
-  ...(process.versions.bun
-    ? [
-        {
-          extends: false,
-          ...transforms,
-          test: {
-            ...testOptions,
-            name: 'bun',
-            env: { ORCA_VITEST_RUNTIME: 'bun' },
-            pool: 'forks',
-            exclude: [...testOptions.exclude, ...NODE_RUNTIME_INCLUDE, measurementFile],
-            sequence: { groupOrder: 1 }
-          }
-        }
-      ]
-    : []),
+  ...(process.versions.bun ? [bunProject] : []),
   nodeProject,
   // Keep the event-loop measurement free of other suites without weakening its limits.
   {
@@ -95,6 +96,18 @@ const projects = [
       maxWorkers: 1,
       sequence: { groupOrder: 2 }
     }
+  },
+  // Preserve the palette test's runtime and budgets while keeping other suites off its CPU.
+  {
+    ...paletteRuntimeProject,
+    test: {
+      ...paletteRuntimeProject.test,
+      name: 'palette-measurement',
+      include: [paletteMeasurementFile],
+      exclude: testOptions.exclude,
+      maxWorkers: 1,
+      sequence: { groupOrder: 3 }
+    }
   }
 ]