diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index a12eec93..def022f7 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -17,7 +17,7 @@ jobs:
 ## This makes sure we're using the current version of the library.
     - run: sudo apt-get install ccache
     - run: make setup
-    - run: make -j $(nproc) smoke-sketches
+    - run: make -j 4 smoke-sketches
   run-google-tests:
     runs-on: ubuntu-20.04
     steps:
@@ -25,7 +25,7 @@ jobs:
 #    - uses: mxschmitt/action-tmate@v3
     - run: sudo apt-get install ccache
     - run: make setup
-    - run: make -j $(nproc) simulator-tests
+    - run: make -j 4 simulator-tests
   check-astyle:
     runs-on: ubuntu-latest
     steps: