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XP Prefetcher Information and Tweaks
XP Prefetcher Information and Tweaks

The XP Prefetcher

Windows XP has a service called the Prefetcher. It basically monitors the different programs that start during startup and helps them launch faster. Very detailed information can be found here. "Logical prefetching is accomplished by tracing frequently accessed pages in supported scenarios and efficiently bringing them into memory when the scenario is launched again. When a supported scenario is started, the transition page faults from mapped files are traced, recording which page of a file is accessed."

To help train the prefetcher you can tell it specific applications to prefetch. I have the instructions for doing this right here.

To find this tool browse to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SessionManager\Memory Management\PrefetchParameters

The important key is EnablePrefetcher. Default value for this SHOULD be3.
1 means to prefetch boot processes only.
2 means prefetch applications only
3 means prefetch both (make sure you're using this)

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SessionManager\Memory Management\PrefetchParameters]

If you have a very low amount of RAM you will want to disable prefetching

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SessionManager\Memory Management\PrefetchParameters\EnablePrefetcher]
Set the value to either 0-Disable.

Cleaning Prefetch

Just like everything else in windows after a while the prefetch ends up with files that haven't been used in quite a while. Every so often you should browse to C:/windows/prefetch and clean out what you don't need.

| Prefetch Applications to make them load quicker |

Written By: Martin Krohn
Date: 6-22-04
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