diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 7103bb0f9b..83b0f02b7c 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -23,9 +23,6 @@ jobs:
       matrix:
         os: [ ubuntu-latest, windows-latest, macOS-latest ]
     runs-on: ${{ matrix.os }}
-    env:
-      RUSTUP_UNPACK_RAM: "26214400"
-      RUSTUP_IO_THREADS: "1"
     steps:
       - uses: actions/checkout@v4
       - name: Install Vulkan SDK
@@ -33,7 +30,9 @@ jobs:
         with:
           vulkan_version: 1.4.321.0
           install_runtime: true
-          cache: true
+          # cache restore on mac is broken
+          # see https://github.com/jakoch/install-vulkan-sdk-action/issues/558
+          cache: ${{ runner.os != 'macOS' }}
           stripdown: true
       - if: ${{ runner.os == 'Linux' }}
         name: Linux - Install native dependencies
@@ -55,8 +54,8 @@ jobs:
       - name: rustc_codegen_spirv test
         run: cargo test -p rustc_codegen_spirv --release --no-default-features --features "use-installed-tools"
 
-      - name: workspace test (excluding examples & difftest)
-        run: cargo test --release --workspace --exclude "example-runner-*" --exclude "difftest*" --no-default-features --features "use-installed-tools,clap"
+      - name: workspace test (excluding examples)
+        run: cargo test --release --workspace --exclude "example-runner-*" --no-default-features --features "use-installed-tools,clap"
 
       # Examples
       - name: cargo check examples
@@ -84,9 +83,6 @@ jobs:
         os: [ ubuntu-latest ]
         target: [ aarch64-linux-android ]
     runs-on: ${{ matrix.os }}
-    env:
-      RUSTUP_UNPACK_RAM: "26214400"
-      RUSTUP_IO_THREADS: "1"
     steps:
       - uses: actions/checkout@v4
       - name: Install Vulkan SDK
@@ -181,8 +177,6 @@ jobs:
         run: cargo fetch --locked --target $TARGET
       - name: cargo fetch --locked difftests
         run: cargo fetch --locked --manifest-path=tests/difftests/tests/Cargo.toml --target $TARGET
-      - name: test difftest
-        run: cargo test -p "difftest*" --release --no-default-features --features "use-installed-tools"
       - name: difftests
         run: cargo run -p difftests --release --no-default-features --features "use-installed-tools"