I hope your not trying to do this in order to increase performance, because WoW is meant to be playable even on 400Mhz computers but if that is what your trying to do, the biggest advantage and performance boost in WoW you would get is by switching your hard drives for SSD drives ($900+) which would speed up instance, world map, level loading times by a lot. But than again switch to WIndows XP for boost in slight performance for WoW. AlsoI repeat it is WoW not some high graphic demanding game so any upgarde change other than SSD Drives would not be noticable by humans!