diff --git a/nixos/modules/image/repart-image.nix b/nixos/modules/image/repart-image.nix
index e40406729900..de03beeafc0b 100644
--- a/nixos/modules/image/repart-image.nix
+++ b/nixos/modules/image/repart-image.nix
@@ -90,8 +90,8 @@ let
   }."${compression.algorithm}";
 
   compressionCommand = {
-    "zstd" = "zstd --no-progress --threads=0 -${toString compression.level}";
-    "xz" = "xz --keep --verbose --threads=0 -${toString compression.level}";
+    "zstd" = "zstd --no-progress --threads=$NIX_BUILD_CORES -${toString compression.level}";
+    "xz" = "xz --keep --verbose --threads=$NIX_BUILD_CORES -${toString compression.level}";
   }."${compression.algorithm}";
 in
   stdenvNoCC.mkDerivation (finalAttrs: