It is more accurate to put it this way:
If you have up-to-date hardware (assuming minimum Core 2 Duo and above (and/or equivelant) with a DX10 class card, you will get a high performance count that is enough to really not care about the difference in performance between XP and Vista (i.e. Vista 112 fps, XP 130). The difference in these results is not THAT noticable.
If you own GeForce 7 series and below (and/or equivelant) then it will seem more obvious that XP performs better than Vista (i.e. Vista 48 fps, XP 62 etc).
So, if you're a gamer who doesn't care about the FPS counter, and have decent hardware, it is alright.....but if you have a single-core machine with a DX9 class card or less, then just stick with XP....cause you won't find games that perform better in Vista over XP. It'll either be the same or less in Vista....generally.
r2rX
