Windows XP Professional x64 Only Seeing 3GB RAM?

Discussion in 'Windows 64bit' started by Dan, Dec 14, 2007.

  1. Dan

    Dan Guest

    Windows XP Professional x64 and 4GB RAM?
    Alright, So with all the development and what not that I do, I decided
    to upgrade my system to 4GB of RAM. Also, due to software
    incompatibilities with Vista, I decided the my only real choice was
    Windows XP Professional x64 for my OS. I ran through the entire
    install, got all my drivers, everything seemed to be going well. I got
    my RAM today in the mail, slapped it in, checked the BIOS, and
    everything looked good. However, once I got into Windows, it only
    shows that I have 3GB available:

    I checked with CPUZ to make sure that it was seeing the full 4GB and
    it was:

    Now correct me if I'm wrong, but I had always thought that XP 64-bit
    supported something like 128GB of why is my system not
    seeing the full 4GB???? Is there some option that I have to enable to
    allow Windows to use the full 4GB???

    Any help would be appreciated, thanks!!
    Dan, Dec 14, 2007
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  2. There are two BIOS settings which may need to be made. Memory Hole is one,
    and may have both hardware and software versions. There is also MTRR, which
    is often not available.

    You may need to update your motherboard BIOS to have these settings
    available. The best place for advice on the settings is your motherboard
    manufacturer's forums.
    Dominic Payer, Dec 14, 2007
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  3. Dan

    PC ME Guest

    I dig working on electrical stuff!
    PC ME, Dec 14, 2007
  4. Dan

    miso Guest

    On my mobo, you need to get into the bios, enter control+F1, which
    adds more features to tweak. Then find "memory remap."
    miso, Dec 14, 2007
  5. Dan

    Dan Guest

    Interesting....I will try that and let you know how it turns out. I
    have an HP laptop though so I don't know how much I can do with the
    This is my motherboard info if that helps:
    Dan, Dec 14, 2007
  6. Dan

    Dan Guest

    No luck.....I can't seem to get into any of the hidded options of the
    BIOS. It's propably something that HP has done to keep me from doing
    it, I'm sure.....
    Grrr....guess I'm just out of luck at this point, unless someones has
    any ideas???
    Dan, Dec 15, 2007
  7. What did HP tell you when you asked a support person?
    Colin Barnhorst, Dec 15, 2007
  8. Dan

    Dan Guest

    They said that it doesn't support 4GB of RAM and that there was
    nothing that they could do....the typical BS answer I'm sure.
    Dan, Dec 15, 2007
  9. It's not BS. I have a box with a mobo that refuses to support 4GB ram under
    Windows x64. It does support 4GB under 32-bit Windows but not 64-bit. It
    does happen. It is a design flaw and would take a different mobo to fix.
    Colin Barnhorst, Dec 15, 2007
  10. Dan

    Dan Guest

    Well I would have though that a motherboard in a system that's hardly
    6 months old would support 4GB of RAM....guess that's just to much to
    ask though.
    Dan, Dec 15, 2007
  11. When a design fails all bets are off. When HP does not offer a configurator
    option for 4GB you can bet that something is up. If you use the
    configurator for an HP d4996t, for example, you will see a 4GB option. On
    other models you won't. That means that HP has been unable to test a system
    with 4GB reliably and therefore won't sell it that way (because they cannot
    support it).
    Colin Barnhorst, Dec 15, 2007
  12. Dan

    Dan Guest

    *shrugs* Well either way....I'm still a bit disappointed about only
    being able to use 3GB of my RAM. Thanks to everyone that helped, I
    really appreciate it!!!!!!
    Dan, Dec 15, 2007
  13. Dan

    Zootal Guest

    Replace your mother board. A good mobo that supports 4GB of ram costs less
    then $100. I'm using a low end Asus M2A-VM, and even that el-cheapo board
    lets me use all 4GB under XP64.
    Zootal, Dec 16, 2007
  14. I agree. Replace the mobo (but research thoroughly, especially the forums).
    Colin Barnhorst, Dec 16, 2007
  15. Dan

    Dan Guest

    I would but I'm guessing that's a bit difficult on a laptop ;) Plus,
    until the system is out of warranty, I really don't want to screw with
    Dan, Dec 16, 2007
  16. Not always easy to do with an OEM machine, such as those from HP and Dell.
    They inevitably have some proprietary, non-standard configuration that makes
    it difficult or impossible to put a regular mobo in their system.
    Charlie Russel - MVP, Dec 16, 2007
  17. Dan

    Zootal Guest

    Ahh, a laptop - that is a different beast entirely! You are pretty much out
    of luck....
    Zootal, Dec 16, 2007
  18. Dan

    Dan Guest

    Yeah....that's kinda the way I'm seeing it....unless a future BIOS
    update fixes it.

    Also, on a totally unrelated note, the newer Dell stuff uses standard
    ATX/MicroATX boards so it's super east to swap. I don't know about
    the HP desktops.
    Dan, Dec 16, 2007
  19. Dan

    jorgen Guest

    A BIOS update won't fix it. The chipset can only do 32-bit addressing,
    so there is no way to not have an overlap when you install 4GB RAM
    jorgen, Dec 16, 2007
  20. Dan

    Dan Guest

    Oh I didn't realize that that chipset could only support 32-bit
    address, that explains a lot. Thanks!!!!
    Dan, Dec 16, 2007
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