added more RAM and it's reporting less RAM

Discussion in 'Asus' started by Walter_S, Sep 6, 2007.

  1. Walter_S

    Walter_S Guest

    I have a P4B533-V. In the three memory slots I had

    DIMM1- 512M
    DIMM2 - 256M
    DIMM3 - 256M
    giving me 1G of RAM.

    I was recently given a stick of 1GB 184-Pin unbuffered DIMM 128Mx64
    DDR PC2700

    I first tried it in slot one:
    DIMM1- 1G
    DIMM2 - 512M
    DIMM3 - 256M

    That didn't boot.

    I then tried:
    DIMM1- 1G
    DIMM2 - 256M
    DIMM3 - 256M

    That boots but Windows says that I have 768M.

    I didn't make any changes to the BIOS.

    What is going on?

    Walter_S, Sep 6, 2007
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  2. Walter_S

    Eric Parker Guest


    What does it report if the only stick is the 1G ?

    Eric Parker, Sep 6, 2007
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  3. You are probably experiencing the same problem that has been around for
    many years with memory. When a board is designed it is made for
    currently available memory. Newer memory may have a design that the
    board doesn't recognize correctly and only part of the memory is usable.
    The newer DDR memory has a different geometry than the older memory
    and may not work correctly with a lot of existing mother boards.
    Michael W. Ryder, Sep 6, 2007
  4. Walter_S

    Walter_S Guest

    With only the 1G installed it reports 256M. I guess the motherboard
    doesn't support this memory.

    Walter_S, Sep 6, 2007
  5. Walter_S

    Walter_S Guest

    That appears to be the case. The 1G is PC2700 and looking at the
    manual it mentions that it supports PC2100.

    Oh well, my current 512 + 256 +256 setup has always been sufficient.
    Except that I recently loaded Microsoft Virtual Machine to play around
    with another copy of XP running in XP and it would have been nice to
    try it with more RAM. But I have nothing I need to do that requires
    more RAM.

    I'm going to put together a new computer anyway once I figure out
    what motherboard to buy -- so I'm reading this group to figure it.

    Walter_S, Sep 6, 2007
  6. Walter_S

    GMAN Guest

    You should be able to run that ram at the PC2100's 266mhz speed, instead of
    the 2700's 333mhz speed
    GMAN, Sep 6, 2007
  7. Walter_S

    Paul Guest

    The page here, does show certain 1GB modules as being compatible.
    If I was buying the memory, I'd want a module that uses 64Mx8 chips.

    This is the Kingston information.

    You can see an example here, the recommended Kingston 1GB module. It
    states it uses 64Mx8 chips.

    In this archived page, you can see a vendor listing a couple kinds of
    1GB modules. The one on the right, is super-cheap, but it uses 128Mx4
    chips, and that exceeds the addressing capabilities of your chipset.
    You need to use one of the more expensive products with 64Mx8 chips.
    Note that, Ebay is a major source of the 128Mx4 crap, and when sold
    it will usually have a "restricted chipset compatibility" warning
    in the advertising copy. I don't really think the speed rating
    is an issue, as PC3200 is backward compatible, and can run at
    DDR400, DDR333, DDR266, or DDR200. So a faster RAM can be used
    for a slower application.

    So if you can find branded memory, with (16) 64Mx8 chips used to
    make the 1GB total memory, that should work.

    The other issue, described in your manual, is the "four bank limit"
    of your chipset memory controller. Practically speaking, you can use
    a max of two sticks of RAM. Two double sided sticks uses up the total
    of four banks of drive signals, and you should consult the manual
    on which slots to use. Thus, the max memory config, is two 1GB
    DIMMs, plugged into the proper two slots. In the downloadable manual
    for P4B533-V, this is documented in section 2.5.2.

    While the motherboard has three slots, not a lot of people own single
    sided memory DIMMs, to make a DS+SS+SS memory configuration useful.
    As an example, Crucial has sold 512MB single sided DIMMs before,
    in which case you could use 1GB DS + 512MB SS + 512MB SS. But it
    is just as easy to shop for 1GB DS + 1GB DS, leaving the third
    slot blank. Most people will acquire and own double sided memory,
    meaning the third slot never gets used.

    Paul, Sep 6, 2007
  8. Walter_S

    DaveW Guest

    That older motherboard's BIOS is apparently unable to fully recognize and
    use a 1 GB stick of RAM.
    DaveW, Sep 6, 2007
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