I would also recommend a Joomla component called “Query Cache” which caches database queries and really helps you go easy on the database server and does speed things up. If you are using xcache or one of the others, the component detects that the caching program is present and running and allows you to use those caching methods. If you are on VPS xcache is already there, as is mysqli and all together, things get mighty fast, mighty quick.
The developer of QCache does not recommend using the component if you are running in legacy mode. He says it will “trash your site”. That said, I have screwed up and had legacy mode on while running QCache and have had no probs.