Quote Originally Posted by Temujin
One warning, though: I've heard of severe performance problems from people who went the "upgrade" instead of "re-install" route with Vista. If your hardware is up to snuff but Vista seems to stutter anyway, maybe that's the issue?
Vista definately likes as much ram as you can throw at it. All the pre-fetching it does means that it can and will use as much as is available.

Regarding a clean install versus a Vista upgrade, the performance improvement that you get from doing a clean install is negligble. Extremetech did an article on this, and found that while more often than not you got a few extra fps from a clean install that some games like Company of Heroes and Doom 3 got slightly more from an Upgrade. Interesting note, Company of Heroes gets better performance on Vista, than on XP. Media Encoding seemed to be improved.

I'll note that their test machine does run 2GB of memory.

Vista Performance Shootout: Upgrade Vs. Clean Installation