In reality your CPU shouldn't be bottlenecking. Say if you had 3 5970s or 3 480s, then yeah it's gonna bottleneck. I have a feeling you have a defective piece of hardware possibly, but anyone else correct me if I'm wrong. Or maybe your card isn't working like it should with a driver or the such possibly.
How good can you run other games? (i.e. Modern Warfare 2, Bad Company 2, etc. some high graphics demanding games)
I have both console and pc. I got it on pc for the mods actually, because the console version gets boring after awhile. Anyway im running on 1440x900, *** compaq screen haha. And i have only recently purchased this computer so i havnt played COD or Bad company 2 sorry..