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preftech - win xp

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by s0lve_it

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can anybody tell me what preftech is and how its managed in windows?

there's no help available, microsoft dont mention it and there are various fragmented discussions about it in various forums

from what i understand its a way of caching programs, but i want to be able to manage how it works

appreciate any feedback

thanks

2 replies

by toivo talikka

In addition to advice how to disable the Prefetcher in Windows XP (available at http://support.microsoft.com/?kbid=307498&sd=RMVP ), Microsoft offers a description at
http://www.microsoft.com/whdc/driver/kernel/XP_kernel.mspx. Search for the heading 'Logical Prefetcher for Faster Boot and Application Launch'.

You can find some info and warning not to play with the Windows XP Prefetcher at
http://dotnetjunkies.com/WebLog/demiliani/archive/2004/11/28/33943.aspx

The author of the book Windows Server Hacks offers this advice about the Prefetch parameter at http://www.windowsdevcenter.com/pub/a/windows/2004/11/09/XP_startup :
"The default value is 3, but this can be changed to 2 since application files usually end up being cached in the RAM cache and hence don't need to be prefetched."

by pclemente2

An instruction that notifies the CPU that a particular cache line will be needed by a following instruction, permitting memory fetch to overlap execution. The prefetch instruction is simply a load that does not use its operand. Current SGI compilers can generate prefetch instructions automatically.

Managing it, what would you like to do... Clear it out ??

Prefetch is one of the commonly overlooked components that can have a significant impact on system boot time. This tweak allows selection of which components will make use of the prefetch parameters. To see which files are gathered using each of the settings, clear the prefetch cache located at C:\Windows\Prefetch and then enable one of the settings. Clear the cache and repeat for each setting.

[Start] [Run] [Regedit]
Registry Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters
Modify/Create the Value Data Type(s) and Value Name(s) as detailed below.
Data Type: DWORD Value // Value Name: EnablePrefetcher
Setting for Value Data: [0 = Disabled / 1 = Application Launch Prefetch / 2 = Boot Prefetch / 3 = Prefetch All]
Exit Registry and Reboot

Just so you know the Default is 3....

Hope it helps

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