Argh. I'm playing with a quad core Mac Pro at work (that has 4gb) and this thing is waaay faster than the mac mini. Depressingly so. I could totally handle this level of performance at home. And this is with a roughly 2+ year old machine.
I also don't notice the weird "slow framerate" effect that I noticed on the Mini, and also on a friends MBP. Perhaps it's a power-saving or heat-saving thing?