diff --git a/bind.spec b/bind.spec
index c67b140..4e3ad7e 100644
--- a/bind.spec
+++ b/bind.spec
@@ -598,15 +598,18 @@ export TSAN_OPTIONS="log_exe_name=true log_path=ThreadSanitizer exitcode=0"
 
 %if %{with UNITTEST}
   pushd build
-  ORIGFILES=$(ulimit -n)
-  ulimit -n 4096 # Requires on some machines with many cores
+  CPUS=$(lscpu -p=cpu,core | grep -v '^#' | wc -l)
+  if [ "$CPUS" -gt 16 ]; then
+    ORIGFILES=$(ulimit -n)
+    ulimit -n 4096 || : # Requires on some machines with many cores
+  fi
   make unit
   e=$?
   if [ "$e" -ne 0 ]; then
     echo "ERROR: this build of BIND failed 'make unit'. Aborting."
     exit $e;
   fi;
-  ulimit -n $ORIGFILES
+  [ "$CPUS" -gt 16 ] && ulimit -n $ORIGFILES || :
   popd
 ## End of UNITTEST
 %endif