lease use the following at your own risk
Microsoft claims Longhorn will be, er, faster

The only reason why its faster is they added a superfetch feature to the prefetcher. If you look at the key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters

you will notice in windows xp

EnablePrefetcher = 3 and you will notice in windows longhorn
EnableSuperfetch = 1

Well, guess what? You can put the EnableSuperfetch = 1 in windows xp and get the same speed.

Wow, Microsoft just added a feature that was already there in xp.