I was once wonderin what is this Prefetch folder that appears inside my Windows directory? Later i found out that it's yet another secret (not anymore tho) that's Micro$oft is havin. It's nothin but a special folder that Windoze uses to store information about software/applications being run that it can use to enhance the loading process. How it ACTUALLY works is still a mystery but there are certain aspects of it that we know that'll be helpful for us to know.

For instance, i have a Firefox shortcut on my desktop which reads "C:\Program Files\Mozilla Firefox\firefox.exe". So if I want to run the browser faster (a little bit?) I can change that to "C:/Program Files/Mozilla Firefox\firefox.exe" /prefetch.

I am not sure about the percentage gain in speed but i'm pretty sure that it'll load the broswer a little faster than before. You can give it a shot and insert '/prefetch' tag at the end of all the shortcuts that's crowding your desktop. If something unexpected happens you can always remove the tag after all exprementing is one if the best way of learning how things work, isn't it?

©2005 t3ctrix

Here is some interesting info concerning the prefetch mecanism.


Windows XP tries to load the programs you need before you need them. While this may speed start times, it can also slow down your system. (more later on that)

When your workstation boots, XP prefetches portions of the files you use most frequently and has any application you've recently run waiting and ready to go. Rather than waiting for you to click an icon to start a program, and then loading all of the associated files, libraries, and pointers necessary to run the program, XP has all the components of your programs preloaded. When you click an icon to start the program, most of the hard work is already done.

On the other hand, XP will prefetch a program even if you use it only once or twice... Which will consume resources, thus slowing down you pc.


Notice that layout.ini file in Prefetch folder ? it contains info related to the disk defragmenter.

It is also said that deleting every entries in this folder will speed up your machine, by cleaning up very old prefetched applications. The Prefetch process will be re-executed when you reboot you computer.


See techrepublic.com for more detailed info.

t3ctrix: Are you sure about this /prefetch switch ? I would say that by default prefetch is implemented, no switch needed.

ehm? hmmm can i delet the fiels in the preftech folder without any risks?

yes. there is no harm deleteing files in the prefetch directory. i usauly do it when i delete unwanted files.( disk cleanup) ..sometimes i include the files on that diectory.

the prfetcher can increase the boottime of applications

it copies the programms or data u use often into the ram.
so the acces to this files will be faster.

the systemboottime will not be affected.


u can start regedit.exe

then go to

hkey_local_maschine
system\currentcontrolset\control\session manager\prefetch parameters

EnablePrefetcher can handel 4 diffrent settings (0 ,1 ,2 or 3)

0:disabled prefecher
1: supervises only the programmdata and merge it at systemstart
2: (serversystem standart) only systemdata(driver and services) optimized
3: often used programms and systemdata

the prefetch-folder will be stored @ %systemroot%\prefetch
(inside data can be deleted, will be collected again)

u can use it also with linkages:

add a `/prefetch:x` (without`) and for x u can use 1,2 or 3 to the link-target

Nice. I had not idea you could change the parameters of prefetch. Only thing I had problem with was the path to that location.

Mine was located in a dif key.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters

kv-