OMW qwik thats the biggest load of crap i have ever heard, maybe he had a problem and did not take the time to figure it out.
I run my vista install just about 7 days a week, with windows xp it would slow down after a few days and i would reboot to get it back up to speed, but with vista its always fast and never gets bogged down nor do i need to restart to reclaim the speed.
Also you know how after 6-12 months xp starts running slow and like crap? vista just keeps giving you the love, does not slow down after months of use like xp, which for me is great because now i don't need to fresh install every 3-6 months .
Anyways back on topic, if your getting 15k with a dual core man, you'll get closer to 18-19k on a quadcore with 3dmark.