All I can say is what I said before, the game needs to be optimized badly. Unless it's an issue of driver support as well, I really dont know my self.
All I know is my 3dMark05 score is 5949, CS:S stress test is 121 fps, so overall my system is pretty fast considering I'm not overclocking a thing and the majority of the hardware in my system is over a year old (don't quote me). Judging from all that, I need to say I can't imagine them not tweaking the game, if my system is stuttering everytime I turn a corner.
I would say, cross your fingers and hope they fix it before release.