diff --git a/.circleci/config.yml b/.circleci/config.yml
index 4b26b975cdcde7ee3a8c0d604928f50210b4ab7d..9e9f4788fe442a675a401c81cc5b3a8c926de5c6 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -79,7 +79,7 @@ jobs:
           name: "Run Tests"
           command: |
             export NIX_PATH=nixpkgs=https://github.com/NixOS/nixpkgs-channels/archive/$(cat nixpkgs.rev).tar.gz
-            nix-build nixos/system-tests.nix -A driver
+            nix-build --max-jobs 1 nixos/system-tests.nix -A driver
 
   build:
     docker: