diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index e49e0cb..354958e 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -26,13 +26,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
-      - uses: actions/cache@v4
-        with:
-          path: |
-            ~/go/pkg/mod
-            ~/go/bin
-            ~/.cache
-          key: media-sdk
 
       - name: Set up SoX resampler and Opus
         run: |
@@ -43,6 +36,23 @@ jobs:
         uses: actions/setup-go@v5
         with:
           go-version: 1.26
+          # setup-go's own cache restores on an exact key only, so any go.sum
+          # change is a full cold build. Restored below instead.
+          cache: false
+
+      # The run_id suffix never pre-exists, so a push always writes a fresh
+      # entry rather than one frozen at the go.sum that first created it.
+      - name: Restore Go caches
+        id: go-cache
+        uses: actions/cache/restore@v4
+        with:
+          path: |
+            ~/.cache/go-build
+            ~/go/pkg/mod
+          key: go-${{ runner.os }}-${{ hashFiles('go.sum') }}-${{ github.run_id }}
+          restore-keys: |
+            go-${{ runner.os }}-${{ hashFiles('go.sum') }}-
+            go-${{ runner.os }}-
 
       - name: Set up gotestfmt
         run: go install github.com/gotesttools/gotestfmt/v2/cmd/gotestfmt@latest
@@ -67,3 +77,14 @@ jobs:
         run: |
           set -euo pipefail
           go test -json -v ./... 2>&1 | gotestfmt
+
+      # Only main writes. Pull requests read main's entry, which keeps ~1 GB
+      # per PR run out of the repo's 10 GB cache budget.
+      - name: Save Go caches
+        if: github.event_name == 'push'
+        uses: actions/cache/save@v4
+        with:
+          path: |
+            ~/.cache/go-build
+            ~/go/pkg/mod
+          key: ${{ steps.go-cache.outputs.cache-primary-key }}