Prefetch files

Archived from groups: microsoft.public.windowsxp.customize (More info?)

Have read that it is OK, and will in fact, speed up your
computer to delete all the .pf files in the Prefetch
folder in Windows..........does anyone know if this is
true? And what will be the consequences of deleting
these files?

Thanks,
Deloy
4 answers Last reply
More about prefetch files
  1. Archived from groups: microsoft.public.windowsxp.customize (More info?)

    Hi,

    From what I have read and heard about prefetch, if you
    clean out the prefetch files, it will speed up the boot,
    since it will not preload the files you access often. On
    the other hand, the frequently access files will not open
    up quickly. From what I have heard, it all depends on how
    big your prefetch gets that determines the speed of
    startup. I could be wrong too, but that is what I get
    from reading up on prefetch and responses I have read in
    the News Groups about it.

    Jeff

    >-----Original Message-----
    >Have read that it is OK, and will in fact, speed up your
    >computer to delete all the .pf files in the Prefetch
    >folder in Windows..........does anyone know if this is
    >true? And what will be the consequences of deleting
    >these files?
    >
    >Thanks,
    >Deloy
    >.
    >
  2. Archived from groups: microsoft.public.windowsxp.customize (More info?)

    Don't bother, the file is constantly changing. In 3 ½ years with XP my prefetch folder has never ever exceeded 129 entries. If you clean out the folder (leave layout.ini) then when you open a program it gets added to the folder as does every subsequent program - you have gained nothing.

    Just let it do its thing.

    --
    Just my 2¢ worth,
    Jeff
    __________in response to__________
    "Jeff" <anonymous@discussions.microsoft.com> wrote in message news:c7bd01c48a44$53f30060$a501280a@phx.gbl...
    | Hi,
    |
    | From what I have read and heard about prefetch, if you
    | clean out the prefetch files, it will speed up the boot,
    | since it will not preload the files you access often. On
    | the other hand, the frequently access files will not open
    | up quickly. From what I have heard, it all depends on how
    | big your prefetch gets that determines the speed of
    | startup. I could be wrong too, but that is what I get
    | from reading up on prefetch and responses I have read in
    | the News Groups about it.
    |
    | Jeff
  3. Archived from groups: microsoft.public.windowsxp.customize (More info?)

    There is a free utility called Windows XP Prefetch Clean and Control that
    will allow you to clear out all entries and set it to monitor boot files
    only, applications only, all files or you can disable it completely.

    "» mrtee «" <hingelicker$@gmail.com> wrote in message
    news:uHhRiUliEHA.1764@TK2MSFTNGP10.phx.gbl...
    Don't bother, the file is constantly changing. In 3 ½ years with XP my
    prefetch folder has never ever exceeded 129 entries. If you clean out the
    folder (leave layout.ini) then when you open a program it gets added to the
    folder as does every subsequent program - you have gained nothing.

    Just let it do its thing.

    --
    Just my 2¢ worth,
    Jeff
    __________in response to__________
    "Jeff" <anonymous@discussions.microsoft.com> wrote in message
    news:c7bd01c48a44$53f30060$a501280a@phx.gbl...
    | Hi,
    |
    | From what I have read and heard about prefetch, if you
    | clean out the prefetch files, it will speed up the boot,
    | since it will not preload the files you access often. On
    | the other hand, the frequently access files will not open
    | up quickly. From what I have heard, it all depends on how
    | big your prefetch gets that determines the speed of
    | startup. I could be wrong too, but that is what I get
    | from reading up on prefetch and responses I have read in
    | the News Groups about it.
    |
    | Jeff
  4. Archived from groups: microsoft.public.windowsxp.customize (More info?)

    I've seen a number of differing views on prefetch, and would like to offer
    some more and different info on why you might want to clean pre-fetch. It
    doesn't stay a constant size for all--it can get too full in the equations
    of some boxes rapidly. I don't think you can hurt yourself deleting
    pre-fetch--it's going to reconstitute, but you may improve boot or
    performance. If one takes a look at a number of articles on Pre-fetch, you
    will come away with the idea that cleaning it or resetting its parameters in
    the registry may speed not only booting, but performance as well, and you
    do not compromise opening a program--it will be reconstituted and you have
    gained something in two significant areas--boot speed and PC performance.

    Google on Pre-Fetch
    http://tinyurl.com/65fyt

    http://techrepublic.com.com/5100-6270_11-5165773.html and here's a
    contrarian view to that:


    http://www.bootdisk.com/bootlist/138.htm

    Pre-fetch Delete Favorably Impacts Boot Time
    http://www.theeldergeek.com/prefetch_parameters_-_altering.htm

    http://www.komando.com/tips_show.asp?showID=6737

    Mark Russonovitch's (Sysinternals) Take on Pre-Fetch
    http://www.techsoup.org/forums/index.cfm?fuseaction=read&forum=2009&id=52366&cid=117&mid=179692

    From Kelly's XP:
    http://www.kellys-korner-xp.com/xp_p.htm

    Prefetch

    Prefetch is a new and very useful technique in Windows XP. However, after
    using XP some time, the Prefetch directory can get full and have obsolete
    links in the Prefetch catalog, which can slow down your computer
    significantly.

    The Prefetcher component in Windows XP is part of the Memory Manager, and
    helps to shorten the amount of time it takes to start Windows and programs.

    Windows XP "monitors" itself and notices which applications are launched
    frequently. It gathers information about these applications and what they
    access with the launch and stores this information in the prefetch folder.
    It then uses this information to "optimize" access to these files so that
    they launch faster.

    Once every three days, by default, Windows XP will perform a partial
    defragmentation and adjust the layout of the disk based upon current use.
    The files to be moved are written in the file Layout.ini (found in the
    Prefetch directory under the System Root directory).

    Suggestion: Open C:\Windows\Prefetch and delete the obsolete files,
    reboot. However, if you don't have a real good
    reason to delete these files, just leave them be.
    Let the system handle this folder.

    If system performance is an issue:

    XP automatically optimizes itself every three days, bootvis forces the
    optimization to happen now rather than having to wait three days. Fast Boot
    /Fast Resume Design: A performance trace visualization tool for use with
    Windows XP systems.

    Bootvis can be downloaded here. For more information click here.

    Manage the Windows Prefetcher Service: Go to Start/Run/Regedit and
    navigate to this key:

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

    Create a new DWORD value, or modify the existing value, called
    "EnablePrefetcher" and set it according to
    (0 = disabled, 1 = Application launch prefetching, 2 = Boot prefetching, 3 =
    Both prefetching). To clear the Prefetcher cache, delete all the files in
    the Prefetch sub-directory (e.g. "C:\Windows\Prefetch").

    Prefetch Defined: This directory is used by the defrag utility to help
    organize the files on your PC for more efficient
    loading.

    "I/O performance is strongly influenced by the layout of files on disk.
    Files and directories that are heavily fragmented or dispersed across the
    disk will hurt performance. While Windows XP will automatically reposition
    some files to improve performance, this will generally be done infrequently
    and will usually include only a small fraction of the files on the disk.
    Therefore, it is a good idea to defragment the disk following an
    installation.

    Once every three days, by default, Windows XP will perform a partial
    defragmentation and adjust the layout of the disk based upon current use.
    The files to be moved are written in the file Layout.ini (found in the
    Prefetch directory under the System Root directory)." Windows XP
    Performance

    Boot Prefetching
    Windows XP speeds up system boot by observing the code and data needed each
    time the system is booted and prefetching the necessary file contents early
    in the boot process. This prefetching is not done until the third boot of
    the system, when sufficient information is available to make the prefetching
    most effective. The files observed during system boot will be used in the
    disk layout process mentioned above. Additional information on the
    prefetcher and the Windows XP boot process can be found at Fast Boot/Fast
    Resume for the Windows Platform.

    Application-Launch Prefetching
    Windows XP also uses prefetching when launching applications. The files and
    the contents of the files accessed by each new process are observed and
    recorded. No prefetching can be done for the first launch of an application,
    so first launches are often considerably slower than subsequent launches.
    About 85% to 90% of the improvement is realized after just one launch of an
    application, with the remaining speed improvement coming after the system
    has had an opportunity to adjust the disk layout with information specific
    to this application. Benchmarking on Windows XP.

    hth,

    Chad Harris


    "» mrtee «" <hingelicker$@gmail.com> wrote in message
    news:uHhRiUliEHA.1764@TK2MSFTNGP10.phx.gbl...
    Don't bother, the file is constantly changing. In 3 ½ years with XP my
    prefetch folder has never ever exceeded 129 entries. If you clean out the
    folder (leave layout.ini) then when you open a program it gets added to the
    folder as does every subsequent program - you have gained nothing.

    Just let it do its thing.

    --
    Just my 2¢ worth,
    Jeff
    __________in response to__________
    "Jeff" <anonymous@discussions.microsoft.com> wrote in message
    news:c7bd01c48a44$53f30060$a501280a@phx.gbl...
    | Hi,
    |
    | From what I have read and heard about prefetch, if you
    | clean out the prefetch files, it will speed up the boot,
    | since it will not preload the files you access often. On
    | the other hand, the frequently access files will not open
    | up quickly. From what I have heard, it all depends on how
    | big your prefetch gets that determines the speed of
    | startup. I could be wrong too, but that is what I get
    | from reading up on prefetch and responses I have read in
    | the News Groups about it.
    |
    | Jeff
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