diff --git a/.github/workflows/coverage.yaml b/.github/workflows/coverage.yaml
index 176948183..3b64e488c 100644
--- a/.github/workflows/coverage.yaml
+++ b/.github/workflows/coverage.yaml
@@ -8,7 +8,7 @@ jobs:
       - name: configure & build
         run: |
           cd lib && ./configure --enable-sm80 && cd ..
-          make -j 64 -C test COVER=1 all.tests
+          make -j 32 -C test COVER=1 all.tests
       - name: tests
         run: |
           make -C test check
diff --git a/.github/workflows/cuda-int-tests.yaml b/.github/workflows/cuda-int-tests.yaml
index f72b6ced6..755bd9731 100644
--- a/.github/workflows/cuda-int-tests.yaml
+++ b/.github/workflows/cuda-int-tests.yaml
@@ -8,7 +8,7 @@ jobs:
       - name: configure & build
         run: |
           cd lib && ./configure --enable-sm80 && cd ..
-          make -j 64 -C test/int/nnc
+          make -j 32 -C test/int/nnc
       - name: integration tests
         run: |
           make -C test/int/nnc test
diff --git a/.github/workflows/ubsan-unit-tests.yaml b/.github/workflows/ubsan-unit-tests.yaml
index 6dd8303cf..21cb5b7de 100644
--- a/.github/workflows/ubsan-unit-tests.yaml
+++ b/.github/workflows/ubsan-unit-tests.yaml
@@ -8,11 +8,11 @@ jobs:
       - name: configure & build
         run: |
           cd lib && ./configure --enable-sm80 && cd ..
-          make -j 64 -C lib ubsan
-          make -j 64 -C bin ubsan
-          make -j 64 -C bin/nnc ubsan
-          make -j 64 -C bin/cuda ubsan
-          make -j 64 -C test ubsan
+          make -j 32 -C lib ubsan
+          make -j 32 -C bin ubsan
+          make -j 32 -C bin/nnc ubsan
+          make -j 32 -C bin/cuda ubsan
+          make -j 32 -C test ubsan
       - name: tests
         run: |
           make -C test test