Vista's engine is powerful enough to crunch the pixels out of ur video card.It can talk directly to GPUs(directx 10 compliant gpu) without accessing the cpu which will give a mammoth performance boost.Further more it can unload and create a pure game environment just like in game consoles and create the ultimate stability for gaming.It unloads all unnecessary services and applications running in the background which are not necessary for gaming.Bet u did not know that games for a few years will be ported on both Xp and vista.That means that a game will support both directx 9 and 10 first time ever