Did you clean your temp files?
Have you tried re-installing?
I am using D3Doverride to enable v-sync and I got a 3-4 fps boost. Then I said f_ck it and I set everything to max, including NVIDIA physx (I have a 6950) in dx10 and I get constant 60 fps. I think dx11 is a joke, and spending 500 dlls on another 6950, PSU and motherboard just to see some 3d brick walls is not worth it. Thanks for your help.