diff --git a/.circleci/build-toolchains.sh b/.circleci/build-toolchains.sh
index 63f47505..b43d2eda 100755
--- a/.circleci/build-toolchains.sh
+++ b/.circleci/build-toolchains.sh
@@ -14,5 +14,5 @@ if [ ! -d "$HOME/$1-install" ]; then
     cd $HOME
 
     # init all submodules including the tools
-    CHIPYARD_DIR=$LOCAL_CHIPYARD_DIR $LOCAL_CHIPYARD_DIR/scripts/build-toolchains.sh $1
+    CHIPYARD_DIR="$LOCAL_CHIPYARD_DIR" NPROC=2 $LOCAL_CHIPYARD_DIR/scripts/build-toolchains.sh $1
 fi