Find your WordPress install sluggish? Caching not making a difference. Try adding the following lines to your MySQL servers my.cnf.
query_cache_type = 1
query_cache_size = 20M

Alot of MySQL default installations have the query_cache_size set to 0 (the default), disabling the cache. By setting it’s value to something greater than 0, it brings the cache, and your site, to life.
Check out the MySQL documentation at for details.