diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 430d5e820a..c279099b88 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -364,20 +364,26 @@ jobs:
         run: |
           cpus=$(nproc)
           busy=$(awk '{ printf "%d", $1 + 0.5 }' /proc/loadavg)
-          mem_gb=$(awk '/^MemAvailable:/ { print int($2 / 1048576) }' /proc/meminfo)
-          jobs=$(( cpus - busy ))
-          jobs=$(( jobs < mem_gb / 3 ? jobs : mem_gb / 3 ))
-          jobs=$(( jobs > 8 ? 8 : jobs ))
-          jobs=$(( jobs < 1 ? 1 : jobs ))
-          echo "cpus=$cpus load=$busy mem_available_gb=$mem_gb -> build jobs $jobs"
-          echo "CMAKE_BUILD_PARALLEL_LEVEL=$jobs" >> "$GITHUB_ENV"
-          echo "CTEST_PARALLEL_LEVEL=$(( jobs > 4 ? 4 : jobs ))" >> "$GITHUB_ENV"
+          mem_mb=$(awk '/^MemTotal:/ { print int($2 / 1024) }' /proc/meminfo)
+          slots=$(( (mem_mb - 2048) / 1024 ))
+          slots=$(( slots < 1 ? 1 : slots ))
+          tests=$(( cpus - busy ))
+          tests=$(( tests < 1 ? 1 : tests ))
+          slot_dir=$CCACHE_DIR/compile-slots
+          mkdir -p -m 1777 "$slot_dir"
+          test -w "$slot_dir"
+          echo "cpus=$cpus load=$busy mem_total_mb=$mem_mb -> build jobs $cpus, cold compiles $slots per host, tests $tests"
+          echo "CMAKE_BUILD_PARALLEL_LEVEL=$cpus" >> "$GITHUB_ENV"
+          echo "CTEST_PARALLEL_LEVEL=$tests" >> "$GITHUB_ENV"
+          echo "CCACHE_PREFIX=$GITHUB_WORKSPACE/tools/compile_slot.sh" >> "$GITHUB_ENV"
+          echo "ANYPS5_COMPILE_SLOT_DIR=$slot_dir" >> "$GITHUB_ENV"
+          echo "ANYPS5_COMPILE_SLOTS=$slots" >> "$GITHUB_ENV"
       - run: cmake -S . -B build $CONFIGURE -DANYPS5_ENABLE_SPIRV_TOOLS=ON "-DCMAKE_EXE_LINKER_FLAGS=$LINKER_FLAGS" "-DCMAKE_SHARED_LINKER_FLAGS=$LINKER_FLAGS" "-DCMAKE_MODULE_LINKER_FLAGS=$LINKER_FLAGS"
       - name: Check that every test executable is registered with ctest
         run: python3 tools/check_test_registration.py build
       - run: cmake --build build -- -l "$(nproc)"
       - run: cmake --build build --target libs -- -l "$(nproc)"
-      - run: ctest --test-dir build --output-on-failure --timeout 120 --output-log ctest.log --output-junit ctest.xml
+      - run: ctest --test-dir build --test-load "$(nproc)" --output-on-failure --timeout 120 --output-log ctest.log --output-junit ctest.xml
         env:
           ANYPS5_REQUIRE_VULKAN: 1
           GALLIUM_OVERRIDE_CPU_CAPS: avx
diff --git a/tools/compile_slot.sh b/tools/compile_slot.sh
new file mode 100755
index 0000000000..2f01329de4
--- /dev/null
+++ b/tools/compile_slot.sh
@@ -0,0 +1,15 @@
+#!/bin/bash
+set -u
+dir=${ANYPS5_COMPILE_SLOT_DIR:?}
+slots=${ANYPS5_COMPILE_SLOTS:?}
+while :; do
+  for ((i = 0; i < slots; i++)); do
+    [ -e "$dir/slot-$i" ] || : >> "$dir/slot-$i"
+    exec {fd}<"$dir/slot-$i"
+    if flock -n "$fd"; then
+      exec "$@"
+    fi
+    exec {fd}>&-
+  done
+  sleep 0.1
+done