diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 51a3dc76e9..a64a568abd 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -295,7 +295,10 @@ jobs:
             -DLLAMA_SANITIZE_${{ matrix.sanitizer }}=ON \
             -DGGML_SANITIZE_${{ matrix.sanitizer }}=ON \
             -DCMAKE_BUILD_TYPE=${{ matrix.build_type }}
-          cmake --build build --config ${{ matrix.build_type }} -j $(nproc)
+          J=$(( $(nproc) / 2 ))
+          if [ $J -lt 1 ]; then J=1; fi
+          echo "Using -j $J"
+          cmake --build build --config ${{ matrix.build_type }} -j $J
 
       - name: Build (no OpenMP)
         id: cmake_build_no_openmp
@@ -307,7 +310,10 @@ jobs:
             -DGGML_SANITIZE_${{ matrix.sanitizer }}=ON \
             -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} \
             -DGGML_OPENMP=OFF
-          cmake --build build --config ${{ matrix.build_type }} -j $(nproc)
+          J=$(( $(nproc) / 2 ))
+          if [ $J -lt 1 ]; then J=1; fi
+          echo "Using -j $J"
+          cmake --build build --config ${{ matrix.build_type }} -j $J
 
       - name: Test
         id: cmake_test
diff --git a/.github/workflows/server.yml b/.github/workflows/server.yml
index 3d342c35f7..f0f9a0ca9f 100644
--- a/.github/workflows/server.yml
+++ b/.github/workflows/server.yml
@@ -72,6 +72,9 @@ jobs:
       - name: Build
         id: cmake_build
         run: |
+          J=$(( (${env:NUMBER_OF_PROCESSORS} + 1) / 2 ))
+          if [ $J -lt 1 ]; then J=1; fi
+          echo "Using -j $J"
           cmake -B build \
             -DLLAMA_BUILD_BORINGSSL=ON \
             -DGGML_SCHED_NO_REALLOC=ON \
@@ -81,7 +84,7 @@ jobs:
             -DLLAMA_SANITIZE_ADDRESS=${{ matrix.sanitizer == 'ADDRESS' }} \
             -DLLAMA_SANITIZE_THREAD=${{ matrix.sanitizer == 'THREAD' }} \
             -DLLAMA_SANITIZE_UNDEFINED=${{ matrix.sanitizer == 'UNDEFINED' }}
-          cmake --build build --config ${{ matrix.build_type }} -j ${env:NUMBER_OF_PROCESSORS} --target llama-server
+          cmake --build build --config ${{ matrix.build_type }} -j $J --target llama-server
 
       - name: Python setup
         id: setup_python