diff --git a/README.md b/README.md
index d129f7a..8b65295 100644
--- a/README.md
+++ b/README.md
@@ -69,6 +69,8 @@ Based on the reported `fps` the GPU is then classified into either `tier: 1 (>=
 | `WEBGL_UNSUPPORTED`      | No WebGL context could be created. `tier` is always 0.                              |
 | `SSR`                    | Running server-side — no `window`, detection skipped.                               |
 
+The `fps` field is populated only for `BENCHMARK` results. All other `type` values leave `fps` as `undefined`.
+
 ## API
 
 ```ts
diff --git a/src/index.ts b/src/index.ts
index 6dc89c0..45bb22a 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -335,8 +335,11 @@ export const getGPUTier = async ({
       aDis === bDis ? aFps - bFps : aDis - bDis
     );
   if (!results.length) {
+    // Commas in cleaned renderers (e.g. "google, swiftshader ...") break
+    // substring matches against blocklist entries — strip them first.
+    const renderForBlocklist = renderer!.replace(/,/g, '');
     const blocklistedModel: string | undefined = BLOCKLISTED_GPUS.find(
-      (blocklistedModel) => renderer!.includes(blocklistedModel)
+      (blocklistedModel) => renderForBlocklist.includes(blocklistedModel)
     );
     if (blocklistedModel) return toResult(0, 'BLOCKLISTED', blocklistedModel);
 
diff --git a/src/internal/blocklistedGPUS.ts b/src/internal/blocklistedGPUS.ts
index da4d717..9570283 100644
--- a/src/internal/blocklistedGPUS.ts
+++ b/src/internal/blocklistedGPUS.ts
@@ -17,7 +17,7 @@ export const BLOCKLISTED_GPUS = [
   'geforce gt 130',
   'geforce gt 330m',
   'geforce gtx 285',
-  'google swiftshader',
+  'swiftshader',
   'intel g41',
   'intel g45',
   'intel gma 4500mhd',
diff --git a/test/index.test.ts b/test/index.test.ts
index 78118c8..bb22933 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -325,6 +325,19 @@ for (const { input, expected } of [
   });
 });
 
+test('SwiftShader is detected as BLOCKLISTED tier 0', async () => {
+  // SwiftShader is Chrome's CPU-based WebGL fallback — no hardware
+  // acceleration, so consumers should treat it as unusable.
+  const result = await getTier({
+    isMobile: false,
+    renderer:
+      'ANGLE (Google, Vulkan 1.3.0 (SwiftShader Device (Subzero) (0x0000C0DE)), SwiftShader driver)',
+  });
+  expect(result.type).toBe('BLOCKLISTED');
+  expect(result.tier).toBe(0);
+  expect(result.gpu).toBe('swiftshader');
+});
+
 test('Apple Silicon desktop Safari — tier-3 BENCHMARK with m-series label', async () => {
   // Safari returns 'Apple GPU' uniformly for M1–M5 with no chip-level
   // discrimination available from WebGL. Base M1 already hits the tier-3
@@ -403,7 +416,7 @@ test('Apple GPU on mobile does NOT take the desktop tier-3 path', async () => {
   },
   {
     expected: {
-      gpu: 'google swiftshader',
+      gpu: 'swiftshader',
     },
     input: {
       isMobile: false,