Windows XP / Beginners

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Accelerate specific applications with prefetch

How the prefetch system operates is often mysterious. Much about the technology is undocumented, so the general public does not know much about it. Sometimes the only way we find out about features of the operating system is when Microsoft uses them. One example of this is with the release of Windows Media Player 9.0. On top of all of the new multimedia technologies that this release brought to Windows was an insight into the unknown world of the Prefetcher. Hidden away in the shortcut to the application in the Start Menu was an application flag that appears to be an option flag for the Windows Prefetcher system.

What does the shortcut look like?

C:\Program Files\Windows Media Player\wmplayer.exe" /prefetch:1.

EnablePrefetcher Options

Value 		Meaning
0 		Prefetching Disable
1 		Application prefetch only
2 		Boot prefetch only
3 		Prefetch both (Default value)

The /prefetch:1 flag does not appear in any documentation released by Microsoft. The only way to investigate what this flag does is to experiment.

Tried to apply this flag to all of the popular programs. When doing so, an increase in loading time during the second application launch, even after a reboot. It is clear that this flag positively affects the loading time of an application. How it does this is unknown, and will remain unknown unless Microsoft decides to share with us the inner workings of the Prefetcher.

This option flag does not work on all applications. The applications that it does not work on tend to be programs that get the option flag confused with a file that you want it to open. For example, when you type mspaint /prefetch:1 at the command prompt, Microsoft Paint will open, giving you an error that it can't load the prefetch bitmap file because it thinks you are trying to send it a bitmap file to open. You will experience this problem with other applications as well, but the vast majority of programs work well with the flag.

You play around with this flag and see if it helps your applications. If you are unclear how to add the flag, follow these steps:

1. Locate the shortcut file that you are interested in modifying to use the prefetch flag.
2. Right-click the Shortcut file and select Properties.
3. Click at the end of the text in the Target textbox and type in /prefetch:1 or any variation of this that you would like to try, such as /prefetch:22. If your shortcut has quotes around the path to the program, place the option flag on the outside of the quotes.
4. Click OK and that's it.

Unfortunately, no list is available of what programs will work with this and what programs will not. If you load a program after modifying a shortcut and you get an error, just remove the option flag that you added and you will be back to normal.

How much improvement in loading time you observe will vary, depending on the speed of your computer, how your PC is configured, and the like, but it's definitely worth a try.