diff --git a/lib/apps.nix b/lib/apps.nix
index 5d26f04..94106d8 100644
--- a/lib/apps.nix
+++ b/lib/apps.nix
@@ -4,7 +4,7 @@ let
     "${pkgs.qemu_kvm}/bin/qemu-kvm"
     "-cpu host"
     "-usbdevice tablet"
-    "-smp $(nproc)"
+    "-smp cores=4"
     "-m 4096"
   ];