Vista Game Stuttering

Greetings..
Recently i've bought myself a new PC in order to enjoy CoX with it's full graphical settings, and i've decided to install Vista Ultimate 32-bit (Mistake? Wish i knew)..

My PC has 4 GB of ram, a GeForce 9800 GX2, an Intel i7 Quad Core processor, and the latest drivers which i installed yesterday.. Plus, i've even installed a hotfix suggested in a similar thread, but nothing seems to be fixing my problem..

It seems that whenever something "happens" in the background or made the mistake to either alt+tab in order to check something or accidently press a window key, the game starts to stutter heavilly, and there is nothing that fixes this issue, unless i close the game completely and re-run it..

Any ideas??
Thank you for your time!

all i can think of, seeing asthough its a new pc, download all the newest drivers, directX10 etc but i play on vista and its fine o:

Given that vista 32 bit can only 4 gig of total ram (including your GFX card) yeah, a mistake, but not a major one.

You may need to find the hotfix as it won't be standard in vista till sp 2.