diff --git a/nixng/containers/hydra/hydra.nix b/nixng/containers/hydra/hydra.nix
index 40eeee1..7da8d1f 100644
--- a/nixng/containers/hydra/hydra.nix
+++ b/nixng/containers/hydra/hydra.nix
@@ -58,6 +58,7 @@ makeSystem {
 
         dbiFile = "/local/dbi";
         config = {
+          compress_num_threads = 4;
           evaluator_max_memory_size = "2048M";
           store_uri = "daemon?secret-key=/secrets/nix-key.private";
           binary_cache_secret_key_file = "/secrets/nix-key.private";