Perfmon logs the notifier points for a page load, allowing you to quickly identify where time is being taken in the page loading cycle. This is a great way to identify areas of code that might be slowing your cart down.
Forum Support Thread

Zen Cart® Versions v1.5.2, v1.5.3
Original Author swguy
Last Updated by swguy - 19 Jul 2014
Downloads 357

Version History

Perfmon   -   Version: 1.1
Note this version is for 1.5.2 and 1.5.3 (and above) only; if you are running an older version of Zen Cart, please use the prior version of this mod.  
Zen Cart® Versions v1.5.2, v1.5.3
Date Added 19 Jul 2014
Author swguy
File Size 9.3 KB
PHP 5.3 Safe? Yes
Downloads 153
Perfmon   -   Version: 1.0
Zen Cart® Versions v1.3.9, v1.5.0, v1.5.1
Date Added 1 Jun 2013
Author swguy
File Size 10.4 KB
PHP 5.3 Safe? Yes
Downloads 204

Zen-Cart, Internet Selling Services, Klamath Falls, OR