diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 6e63333b0da..62c8c5deaaf 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -37,7 +37,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [
-          "macos-14",
+          "macos-14-arm64",
           "ubuntu-latest",
         ]
         python-version: [
@@ -52,15 +52,19 @@ jobs:
         include:
         - { python-version: "3.11", PYTHONOPTIMIZE: 1, REVERSE: "--reverse" }
         - { python-version: "3.10", PYTHONOPTIMIZE: 2 }
+        # SIMD-accelerated builds for x86
+        - { os: "ubuntu-latest", python-version: "3.9", acceleration: "sse4"}
+        - { os: "ubuntu-latest", python-version: "3.12", acceleration: "avx2"}
         # Free-threaded
         - { os: "ubuntu-latest", python-version: "3.13-dev", disable-gil: true }
         # M1 only available for 3.10+
         - { os: "macos-13", python-version: "3.9" }
+        - { os: "macos-13", python-version: "3.9", acceleration: "avx2"}
         exclude:
-        - { os: "macos-14", python-version: "3.9" }
+        - { os: "macos-14-arm64", python-version: "3.9" }
 
     runs-on: ${{ matrix.os }}
-    name: ${{ matrix.os }} Python ${{ matrix.python-version }} ${{ matrix.disable-gil && 'free-threaded' || '' }}
+    name: ${{ matrix.os }} Python ${{ matrix.python-version }} ${{ matrix.acceleration }} ${{ matrix.disable-gil && 'free-threaded' || '' }}
 
     steps:
     - uses: actions/checkout@v4
@@ -108,7 +112,7 @@ jobs:
         GHA_LIBIMAGEQUANT_CACHE_HIT: ${{ steps.cache-libimagequant.outputs.cache-hit }}
 
     - name: Install macOS dependencies
-      if: startsWith(matrix.os, 'macOS')
+      if: startsWith(matrix.os, 'macos')
       run: |
         .github/workflows/macos-install.sh
       env:
@@ -118,6 +122,11 @@ jobs:
       if: "matrix.os == 'ubuntu-latest' && matrix.python-version == '3.12'"
       run: echo "::add-matcher::.github/problem-matchers/gcc.json"
 
+    - name: Set compiler options for optimization
+      if: ${{ matrix.acceleration }}
+      run: |
+        echo "CC=cc -m${{ matrix.acceleration }}" >> $GITHUB_ENV
+
     - name: Build
       run: |
         .ci/build.sh