diff --git a/lib/x11/xcore.js b/lib/x11/xcore.js
index e7c383e..6fcafcf 100644
--- a/lib/x11/xcore.js
+++ b/lib/x11/xcore.js
@@ -101,7 +101,9 @@ XClient.prototype.importRequestsFromTemplates = function(target, reqs)
                client.seq_num++;
 
             // disable long stack trace for the moment, it's too expensive
-            // performance when enabled: 70000 requests finished in 52196 ms, 1341.0989347842747 req/sec
+            // performance when enabled (travis-ci worker, Xfvb): 70000 requests finished in 52196 ms, 1341.0989347842747 req/sec
+            // without: 70000 requests finished in 14904 ms, 4696.725711218465 req/sec
+            // MBPro, XQuartz: with 3600 req/sec, without 24200 req/sec 
             /*
             var err = new Error;
             err.name = reqName;