Might have to try this. I have a GTX 260 896MB, with x8 AA I was getting around 20fps at 1680x1050 with max settings. I turned it down to just x2 AA and it seems to be around a 10 - 20fps improvement, with no noticeable graphics change.
I wouldn't mind a bit more though. Low fps in the middle of a town isn't fun when there's a lot of small rooms, loads of stuff on the floor to get stuck on and a ton full of MP40 wielding Jerrys.