What is the cache process?
In the last few years Google put more and more SEO points on the site loading speed. You may already read this article on How to Improve your Wordpress E-Commerce Site Loading Speed. So one of the best methods to get a better speed it's to use a cache plugin like W3 Total Cache.
My site use cache now, but the sliding cart stooped to work
Supported WP E-commerce versions:
All 3.7.x Series
All 3.8.x Series