Counter Strike Source Fps drop

[nigletnz]

The problem i am having is when i look at other players i have a significant fps drop. When i am in a building with others its fine and looking at walls, but as soon as i go outside and look at others shooting my fps will drop up to 120 fps, so from 300 down to 180 ish. This problem never happened with XP so this is why im posting about it. I know that it is still good fps to some of u but when the fps drops so dramatically my mouse slows aswell so its kinda annoying espeaically since i play sk and strafe alot. Is any1 else having this problem, or know a solution?Cheers

computer specs are:
Windows 7 64-bit OEM
Intel Core i7 CPU 860 @ 2.80Ghz
4 GB RAM DDR3 @ 666MHz
Nvidia GeForce GTX 295

 

[Frostmourne]

Update all your drivers from chipset to dvd firmware and DirectX with the guide in my sig.

 

[nigletnz]

cheers mate will try that now