diff --git a/.github/actions/setup-go/action.yaml b/.github/actions/setup-go/action.yaml
index 76b7c5d87d206..e13e019554a39 100644
--- a/.github/actions/setup-go/action.yaml
+++ b/.github/actions/setup-go/action.yaml
@@ -5,17 +5,42 @@ inputs:
   version:
     description: "The Go version to use."
     default: "1.24.2"
+  use-preinstalled-go:
+    description: "Whether to use preinstalled Go."
+    default: "false"
+  use-temp-cache-dirs:
+    description: "Whether to use temporary GOCACHE and GOMODCACHE directories."
+    default: "false"
 runs:
   using: "composite"
   steps:
+    - name: Override GOCACHE and GOMODCACHE
+      shell: bash
+      if: inputs.use-temp-cache-dirs == 'true'
+      run: |
+        # cd to another directory to ensure we're not inside a Go project.
+        # That'd trigger Go to download the toolchain for that project.
+        cd "$RUNNER_TEMP"
+        # RUNNER_TEMP should be backed by a RAM disk on Windows if
+        # coder/setup-ramdisk-action was used
+        export GOCACHE_DIR="$RUNNER_TEMP""\go-cache"
+        export GOMODCACHE_DIR="$RUNNER_TEMP""\go-mod-cache"
+        export GOPATH_DIR="$RUNNER_TEMP""\go-path"
+        mkdir -p "$GOCACHE_DIR"
+        mkdir -p "$GOMODCACHE_DIR"
+        mkdir -p "$GOPATH_DIR"
+        go env -w GOCACHE="$GOCACHE_DIR"
+        go env -w GOMODCACHE="$GOMODCACHE_DIR"
+        go env -w GOPATH="$GOPATH_DIR"
+
     - name: Setup Go
       uses: actions/setup-go@0a12ed9d6a96ab950c8f026ed9f722fe0da7ef32 # v5.0.2
       with:
-        go-version: ${{ inputs.version }}
+        go-version: ${{ inputs.use-preinstalled-go == 'false' && inputs.version || '' }}
 
     - name: Install gotestsum
       shell: bash
-      run: go install gotest.tools/gotestsum@latest
+      run: go install gotest.tools/gotestsum@3f7ff0ec4aeb6f95f5d67c998b71f272aa8a8b41 # v1.12.1
 
     # It isn't necessary that we ever do this, but it helps
     # separate the "setup" from the "run" times.
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index cb1260f2ee767..625e6a82673e1 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -313,7 +313,7 @@ jobs:
         run: ./scripts/check_unstaged.sh
 
   test-go:
-    runs-on: ${{ matrix.os == 'ubuntu-latest' && github.repository_owner == 'coder' && 'depot-ubuntu-22.04-4' || matrix.os == 'macos-latest' && github.repository_owner == 'coder' && 'depot-macos-latest' || matrix.os == 'windows-2022' && github.repository_owner == 'coder' && 'windows-latest-16-cores' || matrix.os }}
+    runs-on: ${{ matrix.os == 'ubuntu-latest' && github.repository_owner == 'coder' && 'depot-ubuntu-22.04-4' || matrix.os == 'macos-latest' && github.repository_owner == 'coder' && 'depot-macos-latest' || matrix.os == 'windows-2022' && github.repository_owner == 'coder' && 'depot-windows-2022-16' || matrix.os }}
     needs: changes
     if: needs.changes.outputs.go == 'true' || needs.changes.outputs.ci == 'true' || github.ref == 'refs/heads/main'
     timeout-minutes: 20
@@ -326,10 +326,18 @@ jobs:
           - windows-2022
     steps:
       - name: Harden Runner
+        # Harden Runner is only supported on Ubuntu runners.
+        if: runner.os == 'Linux'
         uses: step-security/harden-runner@0634a2670c59f64b4a01f0f96f84700a4088b9f0 # v2.12.0
         with:
           egress-policy: audit
 
+      # Set up RAM disks to speed up the rest of the job. This action is in
+      # a separate repository to allow its use before actions/checkout.
+      - name: Setup RAM Disks
+        if: runner.os == 'Windows'
+        uses: coder/setup-ramdisk-action@79dacfe70c47ad6d6c0dd7f45412368802641439
+
       - name: Checkout
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
@@ -337,6 +345,12 @@ jobs:
 
       - name: Setup Go
         uses: ./.github/actions/setup-go
+        with:
+          # Runners have Go baked-in and Go will automatically
+          # download the toolchain configured in go.mod, so we don't
+          # need to reinstall it. It's faster on Windows runners.
+          use-preinstalled-go: ${{ runner.os == 'Windows' }}
+          use-temp-cache-dirs: ${{ runner.os == 'Windows' }}
 
       - name: Setup Terraform
         uses: ./.github/actions/setup-tf