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Thread: Missing RAM?

  1. #11
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    Re: Missing RAM?

    Hi everyone :
    Thanks again for replies!

    Just to go over some of the pertinent info I garnered so far:

    1) the BIOS is registering all 4 GB of RAM. I therefore have to assume the sticks are OK.
    2) I really do not know what the m/b is other than the computer is a Dimension 8400 with a Pentium 4 CPU (3.2GHz) H/T capable for dual core.
    3) Even though I am running a 64 bit OS, the m/o is only capable of 4GB with 1 GB DDR2 maximum size sticks & 4 memory slots 0-3
    4) Interesting fact: ran memtest (on grub menu) at bootup & RAM is only showing 3GB! Note: this test would void any Nvidia addressing problems as posted, right?


    Here is the memory info from sudo lshw:

    Code:
    *-memory
              description: System Memory
              physical id: 1000
              slot: System board or motherboard
              size: 4GiB
            *-bank:0
                 description: DIMM DDR Synchronous 533 MHz (1.9 ns)
                 product: 1G-UDIMM
                 vendor: Kingston
                 physical id: 0
                 serial: 2C0D2203
                 slot: CHANNEL A DIMM 0
                 size: 1GiB
                 width: 64 bits
                 clock: 533MHz (1.9ns)
            *-bank:1
                 description: DIMM DDR Synchronous 533 MHz (1.9 ns)
                 product: 1G-UDIMM
                 vendor: Kingston
                 physical id: 1
                 serial: 2C0D2303
                 slot: CHANNEL B DIMM 0
                 size: 1GiB
                 width: 64 bits
                 clock: 533MHz (1.9ns)
            *-bank:2
                 description: DIMM DDR Synchronous 533 MHz (1.9 ns)
                 product: 1G-UDIMM
                 vendor: Kingston
                 physical id: 2
                 serial: 2C0DF402
                 slot: CHANNEL A DIMM 1
                 size: 1GiB
                 width: 64 bits
                 clock: 533MHz (1.9ns)
            *-bank:3
                 description: DIMM DDR Synchronous 533 MHz (1.9 ns)
                 product: 1G-UDIMM
                 vendor: Kingston
                 physical id: 3
                 serial: 2C0DE837
                 slot: CHANNEL B DIMM 1
                 size: 1GiB
                 width: 64 bits
                 clock: 533MHz (1.9ns)
    It is quite apparent that all 4 RAM sticks are good & memory is being registered at 4GB.
    :

  2. #12
    Join Date
    Jan 2007
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    3,202

    Re: Missing RAM?

    This situation appears to be a limitation of the Dell Dimension 8400 motherboard design:

    http://support.dell.com/support/edoc....htm#wp1052394

    Specifically "Your computer supports a maximum of 4 GB of memory when you use four 1-GB DIMMs. Current operating systems, such as Microsoft® Windows® XP, can only use a maximum of 4 GB of address space; however, the amount of memory available to the operating system is less than 4 GB. Certain components within the computer require address space in the 4-GB range. Any address space reserved for these components cannot be used by computer memory."

    (This was obviously written ~10 years ago ...).

    However, 3GB is plenty of memory for most typical usage scenarios with a Linux system. If your productivity requirements often need more than that, then you also seriously need a beefier CPU than the P4.
    Last edited by dabl; January 18th, 2013 at 03:19 PM.
    Intel Core i7-950 / Asus P6X58D-E / Nvidia GTX480 / siduction 64-bit on OCZ Revodrive SSD / KDE4.10.2/ Kubuntu 13.04

  3. #13
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    Re: Missing RAM?

    Hi dabl :

    Thank you for your time & reply!

    As you stated the upper RAM limit on the Dim8400 is 4GB. What gets me is this:

    I have been using Ubuntu since 9.04 & my RAM memory alway showed 4GB or there abouts. Now with 12.04, I only get 2.9GB.

    And yes, you are right: this is an old computer!. However, it still works beautifully even when I am running Eclipse or Aptana Studio along with 2 or 3 other programs; and a desktop littered with eye candy.

    As an aside to a previous post: I removed the Nvidia drivers completely & reverted back to X.Org Nouveau driver but to no avail! Same RAM amount.

    Anyway I am declaring this post DEAD! Thank you again dabl & everyone else for the replies and personal time spent on my post.
    :

  4. #14
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    Jan 2007
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    3,202

    Re: Missing RAM?

    There may have been Linux kernel code to compensate for that particular motherboard family, and being of the age that it is, that code may have been dropped as of 12.04. They seem to be dropping older code and drivers fairly regularly now -- the same thing happened for some older video drivers in 12.10.
    Intel Core i7-950 / Asus P6X58D-E / Nvidia GTX480 / siduction 64-bit on OCZ Revodrive SSD / KDE4.10.2/ Kubuntu 13.04

  5. #15
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    Jan 2009
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    Cool Re: Missing RAM?

    Hi dabl :

    Thanks for your persistence!

    I am now wondering if a BIOS upgrade would resolve the RAM puzzle.

    In any case, I am having no problems with the computer. It just bugs me when I cannot explain why something is the way it is!

    Please do not spend any more time on this matter. I really appreciate your efforts as obviously you have spent a deal of time trying to help me.

    Perhaps I can return the favor & help you & others some day in the future.
    Thank you again & have a great day!
    :

  6. #16
    Join Date
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    Ubuntu 10.04 Lucid Lynx

    Re: Missing RAM?

    Previously using 32bit PAE kernel ?
    The default Ubuntu kernel for 32bit is PAE ??

    32bit non PAE = max ram 3.2GB (same as millions of WinXP boxes with 4GB sticks)

    Don't know why your 64bit system does not see 4GB ..

    cat /proc/cpuinfo

    If you spoll thru the output of:
    dmesg
    - you can see details about BAR 64 bit etc
    Last edited by BicyclerBoy; January 19th, 2013 at 10:15 PM. Reason: BAR 64bit

  7. #17
    Join Date
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    Ubuntu 14.04 Trusty Tahr

    Re: Missing RAM?

    Post #5 shows it is 64 bit.

    But sometimes border line RAM shows in BIOS, but Ubuntu does not see it. But I would think it would then only show 3 sticks not all 4?

    Some have just removed RAM cleaned contacts with eraser, and then alcohol to make sure there are no eraser bits and reinstalled. It may be more just reinstalling to make sure everything is seated correctly.
    Oldfred on vacation. Back Sept 9. Will not have much if any Internet access.
    For info on UEFI boot install & repair:
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to close thread when/if answered completely.







  8. #18
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    Re: Missing RAM?

    post #5 tells us nothing about the OP previous "working" setup.
    It could have been 32bit PAE..

    An eraser may make the Au contacts look nice but it bet is not ESD/SMD safe.
    Last edited by BicyclerBoy; January 23rd, 2013 at 10:43 PM. Reason: TLA foobar

  9. #19
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    Smile Re: Missing RAM?

    Hi everyone :

    Just wanted to add some info for update:

    1) last OS was Ubuntu 12.04 (32bit)
    2) the sudo lshw command shows all 4 sticks ( I have to assume all sticks are seated properly & working)

    Thanks again for all I/P. Greatly appreciated!
    :

  10. #20
    Join Date
    Jun 2007
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    11,023

    Re: Missing RAM?

    My question: where is the missing 1GB of RAM?
    Probably mapped for hardware addressing and unless you need a lot of RAM, probably nothing to worry about.
    Code:
    dmesg | grep e820

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