I'm running on XP and I upgraded my Nvidia drivers from 182.x to 185.x yesterday, unfortunately I experienced a noticeable performance loss. How much exactly I have to fraps first. When running on 182.x forcing off VSync gave me a little boost but with the 185.x I saw no difference. So far it sounds all bad for me but the good news I do no longer experience the "Receiving ..." bug mid-game mentioned in this other thread hence I can now fully enjoy multiplayer games.
Are you using Kegety's no bloom, no blur mod yet to lower your shader load, even though it allowed on every server ? I'm giving it a shot now, the blurry zoom as the tank gunner is almost unbearable anyway.
Wish you best of luck with your performance tuning also since we both run similar graphic cards, I'll subscribed to this thread and read up on it in case you achieve some major breakthrough :)