Good post. When you are faced with performance issues one of the #1 things you can do is look at what you can cache.

Can you cache requests? Page renders? Database objects? How about function calls?

Caching isn't a panacea but it is certainly one of tools in your set of optimization tactics.

Other stuff I generally look for when trying to optimize include:

- Connection times and connecting pooling - Memory constraints - Duplication of data