Cleaning Prefetch

jamesfg · Dec 21, 2008

Hi,

I have Windows XP Pro. Is it important to clean the prefetch for the efficient runnng of the computer and, if so, how often?

Thank you.

DavidGP · Dec 21, 2008

Hi

Not really as prefetch is designed as its name suggests to pre fetch common used applications and system files so that they load quicker, yes there can end up in their old entries from applications that have been uninstalled, but they cause no harm.

Small article for you on this http://www.edbott.com/weblog/archives/000743.html

Keep your PC efficient by using something like Ccleaner to tidy up the junk, keep your Antivirus and security applications upto date, keep Windows upto date, and uninstall any applications you dont really need or going to use, make sure that the startup list ao application to the PC is a lean as possible, with only critical applications allowed to start at boot.

jamesfg · Dec 21, 2008

Thank you very much, Halo. I remember experiencing performance degredation after cleaning out my prefetch folder, but I did not associate the slowdown with the prefetch cleaning at the time.

Have a wonderful Holiday season and New Year.

bigbazza · Dec 21, 2008

Thanks for the link, Halo. I didn't know this fact.

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.
Click to expand...

Nowhere have I read this before now. I may just change my defaults (to clean out Prefetch) to not bother.

I usually clean out my Prefetch probably 3-5 times a week and have not really noticed a degradation of my system. Could be because I use Slickrun MagicWords to run my favourite programs (as effectively a Shortcut) direct to the relevant *.exe file. No need for Prefetch, in these cases, IMO. Bazza

DavidGP · Dec 23, 2008

Prefetch is not just a shortcut link Bazza in the typical sense of anything like Slickrun (which is a commandline shortcut manager), its part of the memory manager and basically loads small segments of common used files into memory for quick loading, more info from David Solomon http://msdn.microsoft.com/en-gb/magazine/cc302206.aspx

bigbazza · Dec 24, 2008

Thanks again, Halo

To quote from the link that Halo provided (scroll down to find it)

When the system boots or an application starts, the Cache Manager is called to give it an opportunity to perform prefetching. The Cache Manager looks in the prefetch directory to see if a trace file exists for the prefetch scenario in question. If it does, the Cache Manager calls NTFS to prefetch any MFT metadata file references, reads in the contents of each of the directories referenced, and finally opens each file referenced. It then calls the Memory Manager to read in any data and code specified in the trace that's not already in memory. The Memory Manager initiates all of the reads asynchronously and then waits for them to complete before letting an application's startup continue.
How does this scheme provide a performance benefit? The answer lies in the fact that during typical system boot or application startup, the order of faults is such that some pages are brought in from one part of a file, then from another part of the same file, then pages are read from a different file, then perhaps from a directory, and so on. This jumping around results in moving the heads around on the disk. Microsoft has learned through analysis that this slows boot and application startup times. By prefetching data from a file or directory all at once before accessing another one, this scattered seeking for data on the disk is greatly reduced or eliminated, thus improving the overall time for system and application startup.
Click to expand...

I'm going to have to read this quite a few times until it sinks in. :-D

Bazza

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Halo said: ↑

Prefetch is not just a shortcut link Bazza in the typical sense of anything like Slickrun (which is a commandline shortcut manager), its part of the memory manager and basically loads small segments of common used files into memory for quick loading, more info from David Solomon http://msdn.microsoft.com/en-gb/magazine/cc302206.aspx
Click to expand...

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Cleaning Prefetch

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DavidGP MajorGeeks Forum Administrator - Grand Pooh-Bah Staff Member

bigbazza R.I.P. 14/12/2011 - Good Onya Geek