Don’t Clean Your Windows

If you’re Windows XP machine is getting slower day by day, then you might imagine that clearing out your Windows “Prefetch” folder would somehow speed up your machine.

This is a myth that has been doing the rounds on the internet for several years now, along with several others which are referenced below.

The Prefetch system was added to Windows to improve the operating system’s performance, by saving essential snippets of information about recently used programs and allowing them to be loaded more quickly next time you need them. In the short term it works well and there is evidence that deleting your pre-fetch folder will slow things down as well as lead to longer boot times.

Microsoft MCSA, Larry Miller gave me the full skinny, with references. Deleting disabling prefetch is a “BAD IDEA”, he told me, it will impair performance.”

Prefetch files are used to optimize both boot and applicaton launch times. Application prefetch files are referenced only after application launch has been initiated. Unused or rarely used entries will have virtually no impact on performance. Manual deletion of these files will impair performance and has no benefits. In any event the folder is self cleaning after 128 entries. All of this has been extensively tested.

He adds that for proper prefetch operation it is essential that the Task Scheduler service be enabled and set to Automatic. If it is not prefetch will be crippled, leading, once again, to impaired performance. “Prefetch works well in the short term and long term,” says Miller, “No user action is needed or desirerable. Anyone who suggests otherwise has no understanding of how prefetch works.”

http://home.comcast.net/~SupportCD/XPMyths.html

http://www.edbott.com/weblog/archives/000024.html
http://blogs.msdn.com/ryanmy/archive/2005/05/25/421882.aspx