Clean Your Prefetch To Improve Performance

[tendigitz 0]

Clean Your Prefetch to Improve Performance

 

This is a unique technique for WinXP. We know that it is necessary to scrub registry and TEMP files for Win9X/ME/2000 periodically. Prefetch is a new and very useful technique in Windows XP. However, after using XP some time, the prefetch directory can get full of junk and obsolete links in the Prefetch catalog, which can slow down your computer noticeably.

 

Open your C:\Windows\Prefetch folder and delete those junk files and reboot. It is recommended that you do this every month.

[iGuest 3]

NONSENSE : clean prefetchClean Your Prefetch To Improve Performance

This is a MYTH, known to informed users for a long time. This "tip" is based on a complete misunderstanding of how prefetch works and ignorance of the basic principles of virtual memory. Prefetch does NOT preload applications, or any portion of them, at boot time. Prefetch files are used to optimize both boot and application launch times. Unused or rarely used entries will have virtually no impact on performance, even if in large numbers. In any event the folder is self cleaning after 128 entries. The comparison of prefetch files to temp files is completely invalid. Manual deletion of these files will deprive Windows of a valuable resource, leading to impaired performance, and has NO benefits. All of this has been extensively tested.

References:

http://forums.xisto.com/no_longer_exists/

https://blogs.msdn.microsoft.com/ryanmy/2005/05/25/misinformation-and-the-the-prefetch-flag/

http://forums.xisto.com/no_longer_exists/

The truth about prefetch has been known for a long time. Unfortunately the myth continues to be spread by many uninformed websites.

Larry Miller

Microsoft MCSA

[iGuest 3]

Prefetch mythsClean Your Prefetch To Improve PerformanceWell if prefetch was so great why is performance so lousy on users' PC's running Windows Vista or Windows 7 for that matter. Microsoft should get back to basics, do away with prefetch disaster and build the desktop like they have with Windows Server 2008 R2 ..No prefetch, 400Mb OS RAM usage = lean OS ready for RAM hungry enterprise apps!-reply by Spazzie

[iGuest 3]

Prefetch cacheClean Your Prefetch To Improve Performance

Granted, the prefetch cache has benefits.  The third time you boot up a brand new XP install it will be real quick, and ditto the third time you start each newly installed app.  But by the 1,000th time, it seems as slow as it could ever possibly be.

Defragmenting the hard-drive seems to have little benefit.  In fact, could defragmenting be a bad idea because it can move core OS DLLs away from the 'centre' of the hard disk (by which I mean halfway between the physical centre and the edge - the idea of hard disk optimization is that commonly accessed data is located near this midpoint to reduce seek times [the time it takes the disk head to move across the disk] and I see no evidence that the standard defrag tool respects this...)?

So I'm wondering if, over time, the prefetch cache can become out of date.  Because of system changes over time (including numerous Windows updates), different sections of code will be surely be run on system and application start-up than when first installed.  Will the prefetch cache update itself to reflect this, or should I delete it all so it can be rebuilt again?  (I am thinking that once every six months should be often enough to do this - deleting it weekly is just plain silly.)

Finally, I question why the system can't prefetch everything - why can't all 'read-only' executable files (.EXEs, .DLLs, .SYSs, etc.) that the OS and applications require be fetched into memory in their entirety on first use, or the majority of them preloaded on system start-up in their entirety (rather than the piecemeal scattered pages that happen to be those that are referenced in the first 2 mins [OS] or 30 seconds [app] of running)?  I would hope that there needs only be one copy of NTDLL, KERNEL32, USER32, etc, etc, loaded into memory that is shared by all processes in all sessions.  Scanning my Windows, System32 and System32drivers comes to a total of about 490Mb, so on a system with at least 1Gb RAM wouldn't it make sense for the whole lot to be loaded into memory on boot in one go - which ought to take less than 20sec on a reasonable HDD...?

Jake

-reply by Jake