diff --git a/.github/workflows/build-cache.yml b/.github/workflows/build-cache.yml
new file mode 100644
index 0000000000..dee4272458
--- /dev/null
+++ b/.github/workflows/build-cache.yml
@@ -0,0 +1,39 @@
+name: Generate rust cache for PR builds
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '0 2 * * *' # run at 2 AM UTC
+
+env:
+    CARGO_TERM_COLOR: always
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        submodules: recursive
+    - name: Install Rust toolchain 1.74 (with clippy and rustfmt)
+      run: rustup toolchain install 1.74-x86_64-unknown-linux-gnu && rustup component add clippy --toolchain 1.74-x86_64-unknown-linux-gnu && rustup component add rustfmt --toolchain 1.74-x86_64-unknown-linux-gnu
+    - name: Lint
+      run: cargo clippy --all --all-targets --all-features --profile pr-tests -- -D warnings
+    - name: Lint
+      run: cargo clippy --all --all-targets --no-default-features --profile pr-tests -- -D warnings
+    - name: Format
+      run: cargo fmt --all --check --verbose
+    - name: Build
+      run: cargo build --all-targets --all --all-features --profile pr-tests
+    - name: Check without Halo2
+      run: cargo check --all --no-default-features --profile pr-tests
+    - name: ⚡ Save rust cache
+      uses: actions/cache/save@v3
+      with:
+        path: |
+          ~/.cargo/registry/index/
+          ~/.cargo/registry/cache/
+          ~/.cargo/git/db/
+          target/
+          Cargo.lock
+        key: ${{ runner.os }}-cargo-pr-tests-${{ hashFiles('**/Cargo.lock') }}
diff --git a/.github/workflows/pr-tests.yml b/.github/workflows/pr-tests.yml
index 0590cbb471..a040c4bafd 100644
--- a/.github/workflows/pr-tests.yml
+++ b/.github/workflows/pr-tests.yml
@@ -24,10 +24,12 @@ jobs:
       uses: actions/cache/restore@v3
       with:
         path: |
-          ~/.cargo/registry
-          ~/.cargo/git
-          target
-        key: ${{ runner.os }}-cargo-pr-tests-${{ hashFiles('**/Cargo.toml') }}
+          ~/.cargo/registry/index/
+          ~/.cargo/registry/cache/
+          ~/.cargo/git/db/
+          target/
+          Cargo.lock
+        key: ${{ runner.os }}-cargo-pr-tests-${{ hashFiles('**/Cargo.lock') }}
         restore-keys: |
           ${{ runner.os }}-cargo-pr-tests-
     - name: Install Rust toolchain 1.74 (with clippy and rustfmt)
@@ -45,15 +47,6 @@ jobs:
     - uses: taiki-e/install-action@nextest
     - name: Create tests archive
       run: cargo nextest archive --archive-file tests.tar.zst --cargo-profile pr-tests --workspace --all-features
-    - name: ⚡ Save rust cache
-      if: github.ref == 'refs/heads/main'
-      uses: actions/cache/save@v3
-      with:
-        path: |
-          ~/.cargo/registry
-          ~/.cargo/git
-          target
-        key: ${{ runner.os }}-cargo-pr-tests-${{ hashFiles('**/Cargo.toml') }}
     - name: Upload tests archive
       uses: actions/upload-artifact@v2
       with: