64-bit XP OS uses memory more efficiently than 32-bit?

Discussion in 'Computer Support' started by Spin, Mar 6, 2008.

  1. Spin

    Spin Guest


    Is it true that a 64-bit XP OS will get more out of a 4GB RAM system than a
    32-bit XP OS will? In other words, the 64-bit version will use the RAM more
    efficiently? I imagine the same efficiencies are true for Windows server?
    Spin, Mar 6, 2008
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  2. Spin

    Jim Guest

    It will use all of the 4GB because the memory mapped IO region is far
    removed from the RAM.
    Jim, Mar 6, 2008
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  3. I suggest you ask this question in the
    microsoft.public.windows.64bit.general newsgroup. The folks there are very
    up to date on 64bit questions.

    One reference you might want to look at is:
    and the White Paper by Charlie Russel which is linked in the Related Links
    box on the right. Charlie is one of the most prolific posters in
    64bit.general, which is why I am suggesting that you drop in there.
    Colin Barnhorst, Mar 6, 2008
  4. Spin

    Holz Guest

    If you as 10 people you will get different answers. Depends for what
    type of application, environment, etc.
    Holz, Mar 6, 2008
  5. Spin

    Bob I Guest

    No, nothing as simple as that. 32 bit only has 4 GB address space, 64
    bit is going to allow the full 4 GB of memory to be used. "Efficiently"
    is subject to interpretation.
    Bob I, Mar 6, 2008

  6. It has nothing to do with "efficiency."

    All 32-bit versions of Windows (not just XP) have a 4GB address space.
    That's the theoretical upper limit beyond which you can not go.

    You can't use the entire 4GB of address space. Even though you have a
    4GB address space, you can only use *around* 3.1GB of RAM. That's
    because some of that space is used by hardware and not available to
    the operating system and applications. The amount you can use varies,
    depending on what hardware you have installed, but is usually around

    Note that the hardware is using the address *space*, not the actual
    RAM itself. The rest of the RAM goes unused because there is no
    address space to map it too.

    64-bit versions of Windows do not have the same limitation, and can
    use the entire 4GB.

    However, note that unless you run very memory-hungry applications
    (such as photographic editing or video-editing), even 3GB under
    Windows XP is almost certainly *way* more RAM than you can make
    effective use of. That means that from a practical standpoint, none of
    what I said above will matter.
    Ken Blake, MVP, Mar 6, 2008
  7. Spin

    why? Guest

    On Wed, 5 Mar 2008 21:49:05 -0500, Spin wrote:

    x-post trimmed to 24hshd

    Why orignal x-post to microsoft.public.windows.server.networking?
    Nothing was mentioned about server.networking in the post.

    It's all to do with mapping around the 3.1/3.5GB memory hole and over
    4GB of RAM. But then that's more to do with the BIOS , RAM addressing
    then just which OS.

    You didn however forget, as already mentioned to ask in, or at least
    checking in -

    or via

    Maybe Windows Server General / Setup, list here.

    why?, Mar 6, 2008
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