Missing 128MB RAM?

MERRICKMERRICK In the studio or on a stage
edited December 2004 in Hardware
Hi all,

My 'puter has the following SDRAM Sticks:
DIMM#1
Texas Instruments 256MB PC133 CAS 3

DIMM#2
APACER 128MB PC100 CAS3

I just installed a RAM stick into DIMM#3 of No Name 256MB PC133 CAS 3 RAM (Got it for free)

Now that should be 640MB right? But my system is reporting 512MB.

BTW the Mobo is 100MHz FSB and the bootup screen is showing ~524MB RAM.

So is there a workaround to reclaim that extra 128MB??

Thanks :thumbsup:

Comments

  • DonutDonut Maine New
    edited November 2004
    Is there a limit to how much ram your board will take? (My old shuttle board only took 768 megs.)
    You could try moving the sticks around to see if they will work in different slots and different combinations.
  • Straight_ManStraight_Man Geeky, in my own way Naples, FL Icrontian
    edited November 2004
    Um, check, in BIOS, your frame buffer size. Video frame buffer can be main RAM dedicated to video. That's true of all desktops, frame buffer up to the max you set in BIOS can be reserved for video. BUT, set frame buffer too low, and video will flake in strange ways, or heisitate.

    A real high-end card, with 256 MB RAM, might want 512 MB of frame buffer. From what you say, in specs, try setting the frame buffer to 64 MB and see if 64 MB magically reappears in Windows. IF video quality suffers, change it back to 128 MB. What I used to make this recommnedation is the FSB, BUT if you in fact have a double-pumped 100 MHz FSB (AMD) or a quad-pumped 100 FSB (early Intel P4 and SOME celerons), you might get bad results with a 64 MB frame buffer, and those results will show first when gaming.

    I'd need to know more about your computer and video card to say more, and if you get ZERO change in what Windows sees for RAM after shrinking the Frame Buffer size in BIOS, then get and run MemTest86, please-- it will tell you if one of your sticks is not being used right or is incompatible with the other two, or if one is bad.

    If you still have problems after trying those things, or questions about how to do them, I need to know your motherboard brand and model, what CPU you actually have in the computer, and what video card or video chip (some motherboards have embedded video, a chip for video wired right on the motherboard that uses main RAM for its memory and frame buffer) is in your computer. Then we can chip in and give better advice, ok???
  • ThraxThrax 🐌 Austin, TX Icrontian
    edited November 2004
    MERRICK wrote:
    Hi all,

    My 'puter has the following SDRAM Sticks:
    DIMM#1
    Texas Instruments 256MB PC133 CAS 3

    DIMM#2
    APACER 128MB PC100 CAS3

    I just installed a RAM stick into DIMM#3 of No Name 256MB PC133 CAS 3 RAM (Got it for free)

    Now that should be 640MB right? But my system is reporting 512MB.

    BTW the Mobo is 100MHz FSB and the bootup screen is showing ~524MB RAM.

    So is there a workaround to reclaim that extra 128MB??

    Thanks :thumbsup:

    How many memory banks does the board support? I suspect you have more memory banks than the system can use.
  • GobblesGobbles Ventura California
    edited November 2004
    yeah id go

    dim 1: 256
    dim 2: 256
    dim 3: 128
  • SimGuySimGuy Ottawa, Canada
    edited November 2004
    Does this computer have an old 440BX chipset (or older) by chance?

    Older chipsets can only read low-density SDRAM, and if you bought that 256 MB module today, chances are pretty darn good that it's high-density SDRAM, which the chipset can only see 1/2 of.
  • MERRICKMERRICK In the studio or on a stage
    edited November 2004
    SimGuy wrote:
    Does this computer have an old 440BX chipset (or older) by chance?

    Older chipsets can only read low-density SDRAM, and if you bought that 256 MB module today, chances are pretty darn good that it's high-density SDRAM, which the chipset can only see 1/2 of.

    Why in fact it does! And that's why I come to Short-Media first :D

    Da good news is that I paid nothing for the Ram. it was in a box that a neighbor(?) chucked on my street. Scored a bunch of nice stuff, seems the MOBO was shot but all else is salvageable.

    Thanks guys :thumbsup:
  • MERRICKMERRICK In the studio or on a stage
    edited November 2004
    Hi guys and thanks!

    I F'd up on the thread creation and apparently double posted. Sim_Guy had the dope for me (Old BX chipset only sees half of high density SDRAM)

    http://www.short-media.com/forum/showthread.php?t=23277&goto=newpost
  • tcagletcagle N. Carolina
    edited December 2004
    I have had similar problems w/ RAM in the past only reading 1/2 of the total installed memory. Is there a way to insert faster RAM in an older PC and have the BIOS and/or Windows read the full memory size? In particular, I have an older PIII 933 MHz processor w/ PC133 - 256 MB inserted but the BIOS memory check and Windows XP Pro is only showing 128 MB. Thanks.
  • muddocktormuddocktor
    edited December 2004
    tcagle wrote:
    I have had similar problems w/ RAM in the past only reading 1/2 of the total installed memory. Is there a way to insert faster RAM in an older PC and have the BIOS and/or Windows read the full memory size? In particular, I have an older PIII 933 MHz processor w/ PC133 - 256 MB inserted but the BIOS memory check and Windows XP Pro is only showing 128 MB. Thanks.

    The only way is to find some low density ram that the mobo fully supports, like in the instance above. If you buy it new, it's likely to be expensive though. I do know for a fact that Crucial sells sdram that work properly in older mobos though.
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