Well since your running it at such a low resolution you won't notice anti-aliasing as much as at the higher resolutions, especially if its only 2x. So 640x480 with 2x AA won't look as good as 800x600 with no AA in my opinion anyway.
Edit: yeah i just noticed i misunderstood what you said.....ups.
Some things that you can tweak that really effect your fps is grass distance and grass shadows, at least when your outside, also self shadows and shadow filtering.
Last edited by AgentP; Jan 31, 2011 at 06:22 AM.