Something to look into: I don't know if any of you guys went to RailsConf, but one of the goals of Rails 2.0 is to improve AR through the caching of repeated queries at the AR object level.
I've already done this. Got a minor speed bump.
You have to understand that the majority of the page loading time is in the instantiation of the AR object, not from fetching the db result. At least that's my experience in my app.
