Vista 32 - Page file size on systems with lots of RAM

Discussion in 'Windows Vista Performance' started by Bob H, Jul 1, 2007.

  1. Bob H

    Bob H Guest

    This may be a silly question, but here goes:

    The normal advice used for the minimum Page File size is that it should
    always be larger than the amount of RAM installed - but I wondered if this
    still made sense when you have a lot of RAM installed. I'm seeing a lot of
    posts from people with 3GB or 4GB of RAM, so it seems to be a pertinent issue.
    Taking my specific example, I have 3 GB of RAM, and 4 GB of Page File - so
    have a total memory pool of 7 GB - which presumably takes a fair chunk of
    system resource to manage, and also is more than a 32 bit system should be
    able to cope with anyway.
    In short, should that advice be modified.
     
    Bob H, Jul 1, 2007
    #1
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  2. The normal advice for the pagefile (at least that given by folks who
    actually know what they're doing, anyway) is to leave it alone. There's no
    advantage to artificially making it larger since it will only result in
    wasted disk space and no improvement in performance. There's no advantage
    in forcing it smaller since that could result in programs crashing due to a
    lack of virtual memory for them to use.

    The very old and very incorrect "Set the pagefile to 2.5 times memory"
    advice doesn't even come from Windows at all - but from Unix based operating
    systems.

    --
    Richard G. Harper [MVP Shell/User]
    * NEW! Catch my blog ... http://msmvps.com/blogs/rgharper/
    * PLEASE post all messages and replies in the newsgroups
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    Richard G. Harper, Jul 1, 2007
    #2
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  3. As it was with Windows XP, advice is to allow the system to handle the page
    file. It can do it more efficiently and intelligently than you or I can.

    The only thing I ever do is to place a 2nd pagefile on another drive on the
    2nd IDE controller. I find that if the system drive is being used heavily
    that this 2nd pagefile gets most of the work.

    A 2nd pagefile on the same drive in a separate partition, or on a 2nd hard
    drive connected to the same drive controller as the system drive gives you a
    net gain of *nothing*.

    --


    Regards,

    Richard Urban
    Microsoft MVP Windows Shell/User
    (For email, remove the obvious from my address)
     
    Richard Urban, Jul 1, 2007
    #3
  4. Bob H

    Rick Rogers Guest

    Hi,

    It is a silly question, and based on antiquated ideas. The minimum size of
    the pagefile (assuming you feel the need to do this manually - there really
    is no need to), should be the same as the size of the memory dump your
    system is set to create on system failure. This is determined in the
    advanced system settings under startup and recovery. Anything smaller and
    it won't be created. Anything larger is a waste unless the system
    historically uses more virtual memory, and with 3GB of install ram I suspect
    that will not be an issue.
     
    Rick Rogers, Jul 1, 2007
    #4
  5. Bob H

    Lord Takyon Guest


    The only trouble I found with allowing Vista to manage the page file is that
    it becomes fragmented. I have monitored the page file for a while and Vista
    makes some pretty strange choices sometimes, for example it can be sitting
    idle and after a while Vista would increase the PF, even if it was at under
    20% utilization.

    In the end I just observed how much of the PF I could force to be used by
    loading up loads of apps, and then set it to that +50%. So far my system
    performance has been massively improved.

    The only drawback is that each system is different, as are the uses, so any
    advice would be nothing more than an avenue you could investigate.
     
    Lord Takyon, Jul 1, 2007
    #5
  6. Bob H

    Gerry Guest

    Richard

    An advantage exists if you create a fair size mimimum pagefile on a
    drive
    before the free disk space reduces below 60%. If you do this you will
    gain a contiguous pagefile in the middle of the drive. This helps reduce
    free space fragmentation and consequently file fragmentation. Putting
    the
    pagefile in it's own partition on a second drive has the same affect.
    Creating a contiguous pagefile as I suggested will be advantageous where
    there is no second drive or where a user does not have a third party
    partitioning utility.


    --
    Regards.

    Gerry
    ~~~~
    FCA
    Stourport, England
    Enquire, plan and execute
    ~~~~~~~~~~~~~~~~~~~
     
    Gerry, Jul 1, 2007
    #6
  7. I *make* my pagefile contiguous, wherever I place it. I use PerfectDisk and
    do a boot time defrag. Problem solved.

    --


    Regards,

    Richard Urban
    Microsoft MVP Windows Shell/User
    (For email, remove the obvious from my address)
     
    Richard Urban, Jul 1, 2007
    #7
  8. If you have insufficient RAM in your system, of course the pagefile may
    grow. It will have to place the extra entries wherever they fit. Upon a
    reboot you again have the system pagefile - in one contiguous chunk, if that
    is what you had previously. Then the pagefile will begin to grow again.

    The answer is to install more RAM.

    In 15 months of using Vista I have never had the pagefile out grow it's
    initial setting. I am using 2 gig of RAM.

    --


    Regards,

    Richard Urban
    Microsoft MVP Windows Shell/User
    (For email, remove the obvious from my address)



     
    Richard Urban, Jul 1, 2007
    #8

  9. It's common advice, but it's always been poor advice. Page file
    substitutes for real RAM, so the more RAM you have, the less Page file
    you need.

    In most cases these days, you should probably just accept the default
    settings. It often results in somewhat more than you need, but it
    otherwise doesn't hurt--especially in these days of very cheap large
    hard drives. If you want to manage it yourself, read this article by
    the late MVP Alex Nichol: "Virtual Memory in Windows XP" at
    http://aumha.org/win5/a/xpvm.htm The article is about Windows XP, but
    most of it applies to Vista too.
     
    Ken Blake, MVP, Jul 1, 2007
    #9
  10. Bob H

    Lord Takyon Guest

     
    Lord Takyon, Jul 1, 2007
    #10
  11. Then you, or someone using your computer, has already changed the default
    setting. System managed creates a pagefile about the size of your RAM (mine
    is 2,460,942,336 for 2 gig of installed RAM). I have never, in 15 months of
    using Vista, had actual pagefile usage above 400 meg.

    --


    Regards,

    Richard Urban
    Microsoft MVP Windows Shell/User
    (For email, remove the obvious from my address)



     
    Richard Urban, Jul 1, 2007
    #11
  12. Bob H

    Gerry Guest

    Richard

    Mine's for free <G>!

    --
    Regards.

    Gerry
    ~~~~
    FCA
    Stourport, England
    Enquire, plan and execute
    ~~~~~~~~~~~~~~~~~~~
     
    Gerry, Jul 1, 2007
    #12
  13. Bob H

    Bob H Guest

    Thanks for the replies guys.

    My page file is actually split into two equal parts - each part residing on
    SATA hard disks D & E, so its already set up in this way. I've always set a
    mimimum size to avoid fragmentation as the file grows and shrinks.

    PS - I'm not too worried about the possible waste of hard disk space.
     
    Bob H, Jul 1, 2007
    #13
  14. Bob H

    Lord Takyon Guest

     
    Lord Takyon, Jul 1, 2007
    #14
  15. If pagefile was used only for virtual memory, this would be the end of
    it. A task load of 2G would need a 1.5G page files with 512M
    (assuming it will be able to cope with that RAM:swap ratio), and 512M
    page file with 1.5G RAM, etc.

    It's the above logic that leads me to use 512M pagefile for most XP
    installations, irrespective of whether they have 128M, 256M, 512M or
    more RAM. But I also take steps to ensure the page file is not being
    used for other purposes such as fast user switching or full RAM crash
    dumps, as those scale up with RAM, rather than down as swapping would.

    Aside from fast user switching and full crash dumps, Vista may use the
    pagefile as a dumping ground for other underfootware stuff. I don't
    know the OS well enough to know if this applies to contenders such as
    background defrag, shadow copy, indexing, thumbnailing etc.
    It's hard to interpret the impact of fragmenting the page file. On
    the face of it, it would slow things down if reading the page file
    from one end to the other, but that's rarely how it would be used.

    Let's make a few assumptions (and have these contested by readers
    please, if they are wrong!):
    - in-RAM material that has not changed, is:
    - free to page out, as it doesn't need to be written back to HD
    - cheap to reload from the original source file
    - in-RAM material that has changed, is:
    - costly to page out, as it has to be written back to HD
    - may be written to pagefile rather than original location
    - ultimately may need to be copied to original location

    If this is true, then paging can be expected to first purge material
    that does not need to be written back to disk, and only when that's
    all done, will it start on altered RAM contents that do have to be
    written to disk before something else can page into that RAM area.

    That implies page file access will be mixed with page-back reads from
    unchanged but paged-out files, which will include original OS code
    that would usually be at the "front" of the disk unless updated, then
    it could be anywhere, unless relocated by defrag.

    It will also be mixed with write-paging back to temp files (if not
    pagefile itself) that may be at the "far side" of the disk.

    If both of the above are true, then the winning strategy might be to
    fragment the page file into the file mass, especially if the paging
    manager is smart enough to page using areas of the file that lie
    closest to what is being paged.

    Error Messages Are Your Friends
     
    cquirke (MVP Windows shell/user), Jul 1, 2007
    #15
  16. Bob H

    Gerry Guest

    The method of creating a contiguous pagefile you describe only works if
    you have something like 60% free disk space. If less. when you recreate
    the pagefile and reboot. the process of rebooting fragments other files
    which
    are written first into the space where you expect to have a contiguous
    pagefile.


    --
    Regards.

    Gerry
    ~~~~
    FCA
    Stourport, England
    Enquire, plan and execute
    ~~~~~~~~~~~~~~~~~~~

     
    Gerry, Jul 1, 2007
    #16
  17. Bob H

    wildrex Guest

    thats why i run a mac os10 get sidebar ... ect on 1 gig ram and it can do
    anything this piece of crap vista can do when does this thing go final this
    beta is buggy ooops it is final love the millions of post of trouble with it
    lololol
     
    wildrex, Jul 14, 2007
    #17
  18. Bob H

    sebbelcher Guest

    Hi,

    I don't know a great deal about all this pagefile stuff but from an
    layperson's perspective somethign strikes me as odd, and it is this, from my
    personal experience:

    You have a Windows system with 1GB RAM, it creates a 1gb page file and runs
    your apps alright, bit slow with many things running. So one day you upgrade,
    so now you have a Windows system with 2GB RAM and it creates a pagefile of
    2GB, this gives you 4GB of mappable memory and your apps are flying, the
    pagefile is very occasionally used, you can have the entire Adobe suite open
    and the computer is still responsive.

    So if you upgrade to 4GB of RAM, surely there is no need for the page file
    at all?

    Correct me if I'm wrong but you have moved from a system with 4GB mappable
    memory (2GB RAM, 2GB PF) to a system with 4GB mappable memory (4GB RAM) what
    is the problem?

    Surely there must be a performance advantage in forcing Windows to use just
    RAM?

    Seb.
     
    sebbelcher, Jul 14, 2007
    #18
  19. Bob H

    usasma Guest

    I have 4gB of RAM (on a 32 bit system) and have a 1 gB pagefile on a separate
    drive (static size) for compatibility with a few programs. I have not
    experimented without a pagefile in Vista - but in XP I got along quite well
    without one until a program insisted on it.

    So, in short, the pagefile size is dependent on how your programs use it.
    And, IMO, using a static size to the pagefile reduces the resources needed to
    manage it. Setting it to the minimum size required by the programs that
    you're using will be the most efficient - but that will take some work to
    determine as it's not commonly stated in the System Requirements for a
    program.

    - John
     
    usasma, Jul 24, 2007
    #19
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