diff --git a/darwin/ghc-gitlab-ci.nix b/darwin/ghc-gitlab-ci.nix
index 041ec8609dc85c11f31eb8904d7b4727fe9d8e5d..69e9915270de4e5835e3621f3dac7226e8d4f302 100644
--- a/darwin/ghc-gitlab-ci.nix
+++ b/darwin/ghc-gitlab-ci.nix
@@ -32,6 +32,6 @@ stdenv.mkDerivation {
     export HOME="/Users/builder"
     export PATH="${pkgs.clang_10}/bin:$PATH"
     export FONTCONFIG_FILE=${fonts}
-    export CORES=12
+    export CORES=4
     '';
 }