Some time ago, I Googled for a tweak to speed up the performance of my Windows XP applications, and came across two interesting articles: Gaining Speed: Empty Prefetch on your XP System, and Prefetch Applications to make them load faster.

The first article contains a very long and informative tutorial on what the Prefetch folder does and how ‘cleaning it can improve system performance‘. The latter provides a quick and easy tutorial to ‘speed up loading time of applications‘.

I’d like to point out that both are completely false. They are proven to be myths that don’t work, and actually provide negative effects when used. As quoted directly from Ed Bott’s Windows Expertise Blog:

Cleaning out the Prefetch folder will not improve performance. I have proved this with a stopwatch repeatedly on multiple test systems, and documented the results in Windows XP Inside Out Second Edition. In fact, emptying the Prefetch folder will actually reduce performance, because Windows has to re-create the trace files the next time you run the program. Windows cleans out old files here automatically, and it uses the current information simply as instructions to help load programs more efficiently. If you delete a program, its layout and trace files go unused and are deleted within weeks.

Another post from his weblog clearly states that:

This urban legend got started, apparently, when someone took a close look at the properties of the Windows Media Player shortcut in Windows XP and noticed that the shortcut included this parameter at the end. (See for yourself: Right-click the Media Player shortcut on the Start menu or the Quick Launch bar, click Properties, and look at the value in the Target field, as I’ve done here.)

Based on the quote above, the starters of the urban legend believed that based on the /prefetch:1 parameter found on the Windows Media Player shortcut, adding the same switch on any other application would boost load time and accelerate performance. Ryan Myers, a developer in Microsoft’s Windows Client Performance Team, pointed out that the switch is completely bogus. Based on his statement, the prefetch switch found on the Windows Media Player shortcut only serves as an optimization paremeter for loading resource files that WMP  requires during certain media modes, such as the adequate hashes and link libraries for watching DVD movies, listening to shoutcasts, and viewing online streams. In short, a prefetch flag (/prefetch:#, where # is the number of the WMP mode) is only used to optimize the resource files loaded by WMP on certain circumstances, and not actually boost the performance of any other program with the same switch on its command line.

More info about this topic can be found at:

• http://www.edbott.com/weblog/?p=621
• http://www.edbott.com/weblog/archives/000619.html
• http://blogs.msdn.com/ryanmy/default.aspx

This article has been adapted from my original post at PC Buster.