I want to know too. Mine is a 1ghz with 512mb ram. I've been playing it a bit on the only PC in our house, a PIII 500 with 384mb ram and a 64mb Radeon 9000Pro and it runs ok on the lowest settings.

FYI... it runs OK on my wife's 12" PB. See sig for details. She doesn't complain about much lag at all. But from watching her play, I really need to get her more ram.