I got this info about the registry key from TechRepublic: http://techrepublic.com.com/5100-6270_11-5165773.html?tag=e064# although I did read some similar info from MaximumPC magazine http://www.maximumpc.com/

One of those tips to help out windows xp run quicker:

Delete any files in C:\Windows\Prefetch

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

In the right pane, look for the key named EnablePrefetcher. The value of this key represents how prefetch works on your system. Values you can choose from include: