If anything, shouldn't there be a performance increase on xp since it is a less taxing OS?
On the other hand, Vista might be better optimized for applications and is overall a more evolved OS because it is newer.
Playing the devil's advocate here because this is a debate I'm having right now... whether to go xp 64 bit or vista 64. Of those of you that have it, how do you think xp stacks up to Vista?
And what's the difference between SP1 and SP2?