I remember when I was saying that during the beta, but like you guys pointed out there is slight difference, but honestly, when I'm mowing down other people and the games maxed out otherwise, I don't notice any difference, games just too sexy.
The big difference for the games performance seems to be quads, not actual playing performance, but load screen performance, I have no issues running it maxed out with a tri-core, but anyone with a quad will be in the game and already have a flag capped before I get in. Dual core would most likely be a nightmare.