diff --git a/guix/build/utils.scm b/guix/build/utils.scm
index 8e630ad586..e87066cc02 100644
--- a/guix/build/utils.scm
+++ b/guix/build/utils.scm
@@ -186,7 +186,7 @@ (define (tarball? file-name)
 (define (%xz-parallel-args)
   "The xz arguments required to enable bit-reproducible, multi-threaded
 compression."
-  (list "--memlimit=50%"
+  (list "--memlimit=20%"
         (format #f "--threads=~a" (max 2 (parallel-job-count)))))