[support] Improving performance

[Alison]

Hi Guys and Girls,

can anyone recommend a good general discussion site or place where I can read about Drupal caching. Currently running Memcache and APC -  the PHP accelerator, but not sure whether there would be anything to gain by implementing Drupals caching as well. Wouldn't mind finding some way of measuring the effects of the various performance enhancements. Are there any downsides to Memcache and APC?

Hugs

Alison