The category page aka product-list page was really slow to load, about 25 seconds plus

To troubleshoot Magento’s cpu usage, first enable varien profiler

http://www.techawaken.com/enable-magento-profiler-identify-magento-performance-bottlenecks/

You can also try aoe_profiler

Found out it was the configurable swatches.

Tried the first method in this post.

http://magento.stackexchange.com/questions/69863/configurable-swatches-slow-site-down

My load time went from 25s to 10s. Then I tried the 2nd post which points to https://github.com/wigman/AjaxSwatches

Load time went down 3s

BTW I am running Magento 1.9.2.1