True … your site itself is slow and 100% was before aswell. CloudFlare does speed up your site, but just static content. Your DOM/HTML is by default not static (and should not be) and a Cart always is dynamic. Therefore CloudFlare will not speed them up.
So your nativ PageLoad takes about 4s - 5s. Thats the main problem here.
What I would recommend:
- Try to cache as much as possible (normal sites/productpages etc) static with a Plugin
- check if your Server does have enough ressources and if all recommended and required server-related things are meet. (OpCache, APCu, enough memory_limit) and
What these points do:
- will speed up static pages and take load away from your Server
- will speed up dynamic pages (what the core problem here is)
Another things that could cause this is what your origin Server is far away from your visitors and also from me. But when it comes to “distance as a problem” you will have to use CDNs for propagating even your dynamic DOM/HTML to other regions of the worlds for a better and faster experience.