Vista beta2 64bit does not recognize all my RAM - 4GB

Discussion in 'Windows 64bit' started by Guest, Jun 21, 2006.

  1. Guest

    Guest Guest

    Hi all. I just installed the Vista beta2 64-bit edition. I have 4GB RAM on my
    system and Vista only sees 2.5GB. I thought the 64bit system should be able
    to see all the RAM, that's why I ditched the 32-bit XP.

    I have a Tyan Thunder K8WE motherborard (nForce Pro chipset) with 4GB ECC
    Reg RAM. Anyone got any ideas out there? Perhaps a BIOS setting that I need
    to change?

    Guest, Jun 21, 2006
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  2. Guest

    Mark Dietz Guest

    You should see this:

    Which reads:
    Mark Dietz, Jun 21, 2006
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  3. The problem is that your BIOS is protecting certain memory addresses below
    4GB for use by the BIOS of various PCI cards. There should be a setting in
    the BIOS to do address translation to resolve this, but I don't have a Tyan
    board here to give you the exact steps. You can try poking around to see
    what settings there are on your board, or work with Tyan support - they
    should have an FAQ by now, I would think. If you find it, PLEASE report back
    here so we can capture it for others. Thanks.
    Charlie Russel - MVP, Jun 21, 2006
  4. Guest

    John John Guest

    John John, Jun 21, 2006
  5. This can affect any motherboard which has 4GB of RAM fitted.

    Update the BIOS, if needed, and set MTRR to Discrete, not the default of

    The MTRR setting is usually found in the Advanced - CPU configuration BIOS
    settings, but the setting may not be available with all BIOSes. If the
    setting is not available, only a BIOS update will resolve the issue.

    See and for some background
    Dominic Payer, Jun 21, 2006
  6. yup. Thanks for the reference.
    Charlie Russel - MVP, Jun 22, 2006
  7. At last, here is confirmation that DIIMS don't have to be installed in

    The world has been waiting for this.

    Tony. . .
    Tony Sperling, Jun 22, 2006
  8. Guest

    Zapper Guest

    This is great info, thanks for pointing me this way Charlie.

    I am running an MSI K8N-SLI F
    My bios has 3 options that pertain to 64 bit OS'
    2 Have been covered:
    MTRR Mapping Mode-Should be changed to Discrete-Ok
    S/W/ memory hole Remapping- Should be enabled, correct? (It's description
    is: This field enables software to remap the physical memory to the address
    higher than 00E0)

    This third option seems like it is an either/or with the S/W memory
    Bottom of 32 bit[31:24]IO- This field specifies the memory which could be
    remapped to another address higher than 00E0) settings are [0000-00E0]

    Thanks again to everyone for their help,
    Zapper, Jun 26, 2006
  9. Guest

    Zapper Guest

    Thanks again,
    With your info I was able to go into the bios and it now recognizes 4 GB of
    MSI actually had added a new option for H/W memory hole remapping. I chose
    that one along with MTRR discrete and it looks good.

    Zapper, Jun 26, 2006
  10. Thanks for the report back!
    Charlie Russel - MVP, Jun 26, 2006
  11. Guest

    Zapper Guest

    Sorry to keep spamming you guys..but I just wanted to say how excellent this
    resource is...
    I had put in a technical support request to MSI, and they actually wrote
    back to me and said that I was stuck, nothing I could do about the limited
    Here is their responce.

    "MSI Tech. 06/26/2006 This is the limitation of the mb: Due
    to the South Bridge resource deployment, the system density will only be
    detected up to 3+ GB (not full 4GB) when each DIMM is installed with an 1GB
    memory module"

    Zapper, Jun 26, 2006
  12. That's both sad and funny. Given that their BIOS provides support for
    remapping now. Sigh.


    Charlie Russel - MVP, Jun 26, 2006
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