Windows Vista Forums

Missing RAM with SLI enabled
  1. #1


    Join Date : Apr 2008
    Posts : 9
    Vista Ultimate 32bit SP1
    Local Time: 10:12 AM

    Missing RAM with SLI enabled

    Hallo all..looking for a fix...if possible....if no fix, then at least an explanation..the hows and whys...

    I have Vista 32 Ultimate with SP1.
    Here are the rest of my system specs:
    XFX 780i motherboard--shipped with P02 bios, already updated to P04, which was just released
    Intel Quad Core Q6600 2.4ghz
    4GB G.SKILL 240-Pin DDR2 SDRAM 800 PC2 6400
    2 XFX GeForce 8800 GT 512MB PCIe 2.0--SLI'd
    Creative Soundblaster X-Fi Xtreme Gamer PCI
    WD Raptor 74GB
    Seagate 250GB
    D-Link DWL-AG530 32-bit PCI Wireless Adapter
    2 Pioneer 20X DVD±R DVD Burner Black IDE Model DVR-115DBK

    Yes the bios recognizes all 4GB AND the "My Computer" UI "displays" 4GB.

    I know, though, about the 3GB limit of a 32bit system(I hear people say that Vista 32 utilizes (NOT recognize, but UTILIZE) 4GB of RAM, but I have yet to see any evidence that supports that, so I will stick to the idea that 3GB is the limit)

    I know that the 3GB=System RAM+Video RAM.

    I install 1 Nvdia 8800GT 512mb video card.
    System RAM reads 2.5GB. 3GB of System RAM-the 512 of the video card=2.5GB. goody gumdrops.





    I insall the 2nd Nvidia 8800GT 512 video card and enable SLI.
    System RAM reads 1.5GB?



    Shouldn't it read 2.0GB?? 3GB of System RAM-512 for card 1-512 for card 2=2.0...not 1.5...???

    Where did the missing 500mb go?

    AND IF Vista 32 is supposed to be able to utilize 4GB, then shouldn't my RAM read 3.5 before SLI and 3.0 after SLI???

    I have built and rebuilt, installed and reinstalled and I still come up with the same thing no matter what I try.

    I would love a fix...if not, an explanation as to the hows and whys of what is going on...I would at least just like to understand.

    Thanx all!!

      My System SpecsSystem Spec

  2. #2


    SkyKnites Guest

    RE: Missing RAM with SLI enabled

    sorry if this double posts I got a error when posting.
    32bit OS's can only map 4gb of memory. This includes RAM + video ram, plus
    some system addresses. So your shown windows ram is probably a little less
    then 4gb minus video ram.

    "legend0fthefall" wrote:

    >
    > Hallo all..looking for a fix...if possible....if no fix, then at least
    > an explanation..the hows and whys...
    >
    > I have Vista 32 Ultimate with SP1.
    > Here are the rest of my system specs:
    > XFX 780i motherboard--shipped with P02 bios, already updated to P04,
    > which was just released
    > Intel Quad Core Q6600 2.4ghz
    > 4GB G.SKILL 240-Pin DDR2 SDRAM 800 PC2 6400
    > 2 XFX GeForce 8800 GT 512MB PCIe 2.0--SLI'd
    > Creative Soundblaster X-Fi Xtreme Gamer PCI
    > WD Raptor 74GB
    > Seagate 250GB
    > D-Link DWL-AG530 32-bit PCI Wireless Adapter
    > 2 Pioneer 20X DVD±R DVD Burner Black IDE Model DVR-115DBK
    >
    > Yes the bios recognizes all 4GB AND the "My Computer" UI "displays"
    > 4GB.
    >
    > I know, though, about the 3GB limit of a 32bit system(I hear people say
    > that Vista 32 utilizes (NOT recognize, but UTILIZE) 4GB of RAM, but I
    > have yet to see any evidence that supports that, so I will stick to the
    > idea that 3GB is the limit)
    >
    > I know that the 3GB=System RAM+Video RAM.
    >
    > I install 1 Nvdia 8800GT 512mb video card.
    > System RAM reads 2.5GB. 3GB of System RAM-the 512 of the video
    > card=2.5GB. goody gumdrops.
    >
    > [image:
    > http://i120.photobucket.com/albums/o...beforeSLI.jpg]
    >
    > I insall the 2nd Nvidia 8800GT 512 video card and enable SLI.
    > System RAM reads 1.5GB?
    >
    > [image:
    > http://i120.photobucket.com/albums/o.../afterSLI.jpg]
    >
    > Shouldn't it read 2.0GB?? 3GB of System RAM-512 for card 1-512 for card
    > 2=2.0...not 1.5...???
    >
    > Where did the missing 500mb go?
    >
    > AND IF Vista 32 is supposed to be able to utilize 4GB, then shouldn't
    > my RAM read 3.5 before SLI and 3.0 after SLI???
    >
    > I have built and rebuilt, installed and reinstalled and I still come up
    > with the same thing no matter what I try.
    >
    > I would love a fix...if not, an explanation as to the hows and whys of
    > what is going on...I would at least just like to understand.
    >
    > Thanx all!!
    >
    >
    > --
    > legend0fthefall
    >

      My System SpecsSystem Spec

  3. #3


    SkyKnites Guest

    RE: Missing RAM with SLI enabled

    check for a remapping feature in your bios

    "legend0fthefall" wrote:

    >
    > Hallo all..looking for a fix...if possible....if no fix, then at least
    > an explanation..the hows and whys...
    >
    > I have Vista 32 Ultimate with SP1.
    > Here are the rest of my system specs:
    > XFX 780i motherboard--shipped with P02 bios, already updated to P04,
    > which was just released
    > Intel Quad Core Q6600 2.4ghz
    > 4GB G.SKILL 240-Pin DDR2 SDRAM 800 PC2 6400
    > 2 XFX GeForce 8800 GT 512MB PCIe 2.0--SLI'd
    > Creative Soundblaster X-Fi Xtreme Gamer PCI
    > WD Raptor 74GB
    > Seagate 250GB
    > D-Link DWL-AG530 32-bit PCI Wireless Adapter
    > 2 Pioneer 20X DVD±R DVD Burner Black IDE Model DVR-115DBK
    >
    > Yes the bios recognizes all 4GB AND the "My Computer" UI "displays"
    > 4GB.
    >
    > I know, though, about the 3GB limit of a 32bit system(I hear people say
    > that Vista 32 utilizes (NOT recognize, but UTILIZE) 4GB of RAM, but I
    > have yet to see any evidence that supports that, so I will stick to the
    > idea that 3GB is the limit)
    >
    > I know that the 3GB=System RAM+Video RAM.
    >
    > I install 1 Nvdia 8800GT 512mb video card.
    > System RAM reads 2.5GB. 3GB of System RAM-the 512 of the video
    > card=2.5GB. goody gumdrops.
    >
    > [image:
    > http://i120.photobucket.com/albums/o...beforeSLI.jpg]
    >
    > I insall the 2nd Nvidia 8800GT 512 video card and enable SLI.
    > System RAM reads 1.5GB?
    >
    > [image:
    > http://i120.photobucket.com/albums/o.../afterSLI.jpg]
    >
    > Shouldn't it read 2.0GB?? 3GB of System RAM-512 for card 1-512 for card
    > 2=2.0...not 1.5...???
    >
    > Where did the missing 500mb go?
    >
    > AND IF Vista 32 is supposed to be able to utilize 4GB, then shouldn't
    > my RAM read 3.5 before SLI and 3.0 after SLI???
    >
    > I have built and rebuilt, installed and reinstalled and I still come up
    > with the same thing no matter what I try.
    >
    > I would love a fix...if not, an explanation as to the hows and whys of
    > what is going on...I would at least just like to understand.
    >
    > Thanx all!!
    >
    >
    > --
    > legend0fthefall
    >

      My System SpecsSystem Spec

  4. #4


    Colin Barnhorst Guest

    Re: Missing RAM with SLI enabled

    With the BIOS reserving memory for memory-mapped IO for your two 512mb video
    cards and some other devices I am not surprised that you are showing 2.5GB
    available for user programs. That is about right. My systems range from
    2.2GB to 3.5GB. The 3GB number you cite is largely fictional since the
    range across various machines is quite wide. I have seen the most
    frequently cited number here at around 3.2GB. Your math result of
    subtracting 512mb from 3GB is irrelevant since 3GB is not a Windows
    limitation but just a commonly cited number for the user space. The mobo
    manufacturer plays the major role in what is hidden from the user under
    32bit Windows.

    "legend0fthefall" <legend0fthefall.37oa87@xxxxxx-mx.forums.net> wrote in message
    news:legend0fthefall.37oa87@xxxxxx-mx.forums.net...

    >
    > Hallo all..looking for a fix...if possible....if no fix, then at least
    > an explanation..the hows and whys...
    >
    > I have Vista 32 Ultimate with SP1.
    > Here are the rest of my system specs:
    > XFX 780i motherboard--shipped with P02 bios, already updated to P04,
    > which was just released
    > Intel Quad Core Q6600 2.4ghz
    > 4GB G.SKILL 240-Pin DDR2 SDRAM 800 PC2 6400
    > 2 XFX GeForce 8800 GT 512MB PCIe 2.0--SLI'd
    > Creative Soundblaster X-Fi Xtreme Gamer PCI
    > WD Raptor 74GB
    > Seagate 250GB
    > D-Link DWL-AG530 32-bit PCI Wireless Adapter
    > 2 Pioneer 20X DVD±R DVD Burner Black IDE Model DVR-115DBK
    >
    > Yes the bios recognizes all 4GB AND the "My Computer" UI "displays"
    > 4GB.
    >
    > I know, though, about the 3GB limit of a 32bit system(I hear people say
    > that Vista 32 utilizes (NOT recognize, but UTILIZE) 4GB of RAM, but I
    > have yet to see any evidence that supports that, so I will stick to the
    > idea that 3GB is the limit)
    >
    > I know that the 3GB=System RAM+Video RAM.
    >
    > I install 1 Nvdia 8800GT 512mb video card.
    > System RAM reads 2.5GB. 3GB of System RAM-the 512 of the video
    > card=2.5GB. goody gumdrops.
    >
    > [image:
    > http://i120.photobucket.com/albums/o...beforeSLI.jpg]
    >
    > I insall the 2nd Nvidia 8800GT 512 video card and enable SLI.
    > System RAM reads 1.5GB?
    >
    > [image:
    > http://i120.photobucket.com/albums/o.../afterSLI.jpg]
    >
    > Shouldn't it read 2.0GB?? 3GB of System RAM-512 for card 1-512 for card
    > 2=2.0...not 1.5...???
    >
    > Where did the missing 500mb go?
    >
    > AND IF Vista 32 is supposed to be able to utilize 4GB, then shouldn't
    > my RAM read 3.5 before SLI and 3.0 after SLI???
    >
    > I have built and rebuilt, installed and reinstalled and I still come up
    > with the same thing no matter what I try.
    >
    > I would love a fix...if not, an explanation as to the hows and whys of
    > what is going on...I would at least just like to understand.
    >
    > Thanx all!!
    >
    >
    > --
    > legend0fthefall

      My System SpecsSystem Spec

  5. #5


    Join Date : Apr 2008
    Posts : 9
    Vista Ultimate 32bit SP1
    Local Time: 10:12 AM


      Thread Starter

    Re: Missing RAM with SLI enabled

    Quote Originally Posted by SkyKnites View Post
    sorry if this double posts I got a error when posting.
    32bit OS's can only map 4gb of memory. This includes RAM + video ram, plus
    some system addresses. So your shown windows ram is probably a little less
    then 4gb minus video ram.
    [/quote]

    Thanx for the answer!!

    But still, under that reasoning....I don't have 2.5 GB of video ram, I have 1 GB

    So I should be showing 2.7-3.2 GB NOT 1.5....

      My System SpecsSystem Spec

  6. #6


    Join Date : Apr 2008
    Posts : 9
    Vista Ultimate 32bit SP1
    Local Time: 10:12 AM


      Thread Starter

    Re: Missing RAM with SLI enabled

    Quote Originally Posted by SkyKnites View Post
    check for a remapping feature in your bios

    "
    [/quote]

    Hmmm

    I took a trip through my bios a few hours ago...

    I am a little wet under the collar when it comes to fiddling with the bios...

    What precisely might I be looking for??

      My System SpecsSystem Spec

  7. #7


    Join Date : Apr 2008
    Posts : 9
    Vista Ultimate 32bit SP1
    Local Time: 10:12 AM


      Thread Starter

    Re: Missing RAM with SLI enabled

    Quote Originally Posted by Colin Barnhorst View Post
    With the BIOS reserving memory for memory-mapped IO for your two 512mb video
    cards and some other devices I am not surprised that you are showing 2.5GB
    available for user programs. That is about right. My systems range from
    2.2GB to 3.5GB. The 3GB number you cite is largely fictional since the
    range across various machines is quite wide. I have seen the most
    frequently cited number here at around 3.2GB. Your math result of
    subtracting 512mb from 3GB is irrelevant since 3GB is not a Windows
    limitation but just a commonly cited number for the user space. The mobo
    manufacturer plays the major role in what is hidden from the user under
    32bit Windows.
    That 2.5 is with 1 video card though...

    How in the world would adding another video card drop it another gig??

    If Vista really does utilize 4GB, wouldn't my physical memory read 2.7-3.2 GB?? Instead it is reading 1.5gb.

    I have 1GB of video memory, not 2.5GB. That is A LOT of missing memory..

      My System SpecsSystem Spec

  8. #8


    jabloomf1230 Guest

    Re: Missing RAM with SLI enabled

    You know that you can check it yourself, don't you? Go into the Windows
    Control Panel's Device Manager and see what memory addresses are being
    used by each hardware device. For example, on the machine that I am
    typing from, the nVidia 7950 GX2 (single card, dual GPU) shows memory
    address usage at:

    000A0000-000BFFFF
    B0000000-BFFFFFFF
    C0000000-CFFFFFFF
    DB000000-DEFFFFFF

    The last hex number(DEFFFFFF)is approximately @ 3.7 GB decimal. There
    are a bunch of other devices using memory addresses and some of them
    also may be related to the video card. Keep in mind that every video
    card might be implemented differently. I sure that someone has written a
    piece of software that will display a graphical map of the entire
    address space for a specific machine. Here's a generic explanation:

    http://www.codinghorror.com/blog/archives/000811.html

    legend0fthefall wrote:

    > Colin Barnhorst;679579 Wrote:

    >> With the BIOS reserving memory for memory-mapped IO for your two 512mb
    >> video
    >> cards and some other devices I am not surprised that you are showing
    >> 2.5GB
    >> available for user programs. That is about right. My systems range from
    >> 2.2GB to 3.5GB. The 3GB number you cite is largely fictional since the
    >> range across various machines is quite wide. I have seen the most
    >> frequently cited number here at around 3.2GB. Your math result of
    >> subtracting 512mb from 3GB is irrelevant since 3GB is not a Windows
    >> limitation but just a commonly cited number for the user space. The
    >> mobo
    >> manufacturer plays the major role in what is hidden from the user under
    >> 32bit Windows.
    >>
    >>
    >
    > That 2.5 is with 1 video card though...
    >
    > How in the world would adding another video card drop it another gig??
    >
    > If Vista really does utilize 4GB, wouldn't my physical memory read
    > 2.7-3.2 GB?? Instead it is reading 1.5gb.
    >
    > I have 1GB of video memory, not 2.5GB. That is A LOT of missing
    > memory..
    >
    >

      My System SpecsSystem Spec

  9. #9


    Colin Barnhorst Guest

    Re: Missing RAM with SLI enabled

    I have 3.5GB available on one of my computers running Vista Ultimate x86.
    Obviously it varies according to the hardware. I suggest you check with the
    mobo manufacturer about what is going on with the machine. In any case,
    there is no automatic 1GB deduction nor is there an arbitrary ceiling at 3GB
    for the user space. You just have to look at the specific computer to see
    what is being mapped out.

    "legend0fthefall" <legend0fthefall.37olc3@xxxxxx-mx.forums.net> wrote in message
    news:legend0fthefall.37olc3@xxxxxx-mx.forums.net...

    >
    > Colin Barnhorst;679579 Wrote:

    >> With the BIOS reserving memory for memory-mapped IO for your two 512mb
    >> video
    >> cards and some other devices I am not surprised that you are showing
    >> 2.5GB
    >> available for user programs. That is about right. My systems range from
    >> 2.2GB to 3.5GB. The 3GB number you cite is largely fictional since the
    >> range across various machines is quite wide. I have seen the most
    >> frequently cited number here at around 3.2GB. Your math result of
    >> subtracting 512mb from 3GB is irrelevant since 3GB is not a Windows
    >> limitation but just a commonly cited number for the user space. The
    >> mobo
    >> manufacturer plays the major role in what is hidden from the user under
    >> 32bit Windows.
    >>
    >>
    >
    > That 2.5 is with 1 video card though...
    >
    > How in the world would adding another video card drop it another gig??
    >
    > If Vista really does utilize 4GB, wouldn't my physical memory read
    > 2.7-3.2 GB?? Instead it is reading 1.5gb.
    >
    > I have 1GB of video memory, not 2.5GB. That is A LOT of missing
    > memory..
    >
    >
    > --
    > legend0fthefall

      My System SpecsSystem Spec

  10. #10


    Kerry Brown Guest

    Re: Missing RAM with SLI enabled

    >

    > I would love a fix...if not, an explanation as to the hows and whys of
    > what is going on...I would at least just like to understand.
    >

    If you need, or just want, to use all your RAM the solution is to switch to
    a 64 bit OS. Yes, that may introduce other problems but it is the only way
    to use 4 GB or more of RAM with Windows.

    --
    Kerry Brown
    MS-MVP - Windows Desktop Experience: Systems Administration
    http://www.vistahelp.ca/phpBB2/




      My System SpecsSystem Spec

Missing RAM with SLI enabled problems?

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