Yet another Web site posted yet another “tip” today recommending that you clean out your Prefetch folder to improve performance of Windows . Researchers are repeatedly writing about it that clearing the prefetch is no way to improve the performance of the machine but it seems that this bogus advise doesnt seem to end !!!
Ryan Myers, a developer on Microsoft’s Windows Client Performance Team says that
" XP systems have a Prefetch directory underneath the windows root directory, full of .pf files — these are lists of pages to load. The file names are generated from hashing the EXE to load — whenever you load the EXE, we hash, see if there’s a matching (exename)-(hash).pffile in the prefetch directory, and if so we load those pages. (If it doesn’t exist, we track what pages it loads, create that file, and pick a handful of them to save to it.) So, first off, it is a bad idea to periodically clean out that folder as some tech sites suggest. For one thing, XP will just re-create that data anyways; secondly, it trims the files anyways if there’s ever more than 128 of them so that it doesn’t needlessly consume space. So not only is deleting the directory totally unnecessary, but you’re also putting a temporary dent in your PC’s performance. "
Bottom line: You will not improve Windows performance by cleaning out the Prefetch folder. You will, in fact, degrade Windows performance by cleaning out the Prefetch folder.
WHATS THE MYTH ( ITS NOT WHAT IT LOOKS LIKE AND WHAT YOU THINK LIKE !!!! )
Scenario 1 :
As you boot your notebook or access programs on your notebook/desktop, XP’s prefetcher copies portions of those files to the Prefetch area of your hard drive --- THIS IS WHAT YOU THINK !!!!! That’s completely wrong.
What happens :
The files in the Prefetch folder contain lists of pages that that should be loaded when a program starts. Each file is essentially an index. Windows XP doesn’t copy portions of any files to the Prefetch folder.
Scenario 2 :
When your desktop/notebook boots, XP prefetches portions of the files you use most frequently and has any application you’ve recently run waiting and ready to go ---THIS IS WHAT YOU THINK !!!!! This is equally absurd.
What happens :
If this were true, it would mean that Windows was actually loading into memory every program you’ve ever used, every time you start Windows. That’s not the way it works at all. When your PC starts up, Windows looks in the Prefetch folder to determine how best to load Windows. It doesn’t do a thing with the .pf files for applications (unless, of course, you’ve configured one of those apps to start up with Windows).
The .pf files don’t get used at all until you run a program. What actually happens when you click an icon is that Windows uses the information in the Prefetch folder to decide which program segments to load and in what order to load those pages.
Scenario 3:
The drawback to prefetching is that XP will prefetch a program even if you use it only once or twice. XP will retain a copy of a portion of it in the Prefetch folder. From there, it will prefetch the program, taking resources from your workstation even though you may have no intention of ever using the program again---THIS IS WHAT YOU THINK !!!!! Think ALIKE
What happens :
When you run a program, Windows creates a .pf file for it in the Prefetch folder. When you run the program again, Windows looks for this .pf file and uses it to determine how to load the program. The hash doesn’t contain any portion of the original program code. If you never run the program again, that .pf file never gets used, and in fact it gets deleted eventually.
