Please help - G3 400Mhz Lombard recognizes 256MB SODIMM as 128MB?

Discussion in 'Macintosh Computers' started by ran, Jan 13, 2004.

  1. ran macrumors newbie

    Jan 13, 2004
    Hi all!

    I've been trying to upgrade the memory of my PowerBook G3 400mhz (no firewire, just USB) Lombard so as to run OS X.

    I originally have 2 x 64MB modules...and I wanted to upgrade to 2 x 256 MB. I though the Lombard could take upto 512Mb of RAM.

    I bought one 256MB module (used from a Compaq laptop) but the G3 Powerbook will only recognize this as a 128MB module!

    Why? Is there something wrong with the module or the laptop?

    any help would be appreciated...

  2. Dreadnought macrumors 68020


    Jul 22, 2002
    Almere, The Netherlands
    Thst machine can indeed hold two sticks of 256 mb. So it isn't the Mac, or something is really screwed in there. It's probably the Ram. Is the ram double sided? That could be the reason that your mac is only recognizing half the amount of it!
  3. jkieffer72 macrumors member

    Nov 4, 2003
    I've experienced the same issue, for what it's worth... I have also experienced the same issue with my Bondi Blue 233mhz iMac...

    Doing some comparison shopping on Ebay, it seems that perhaps the 256mb module you need would have 16 chips, rather than 8 chips... Does the module you're using have 8 chips?

    I've also had an issue where the 256mb chip would not be recognized at all in the bottom slot, but would be recognized as 128mb in the top slot.
  4. ran thread starter macrumors newbie

    Jan 13, 2004
    Thanks for your responses!

    I've received some feedback on the issue..and we may have come up with a possible cause:

    The memory I put in was a PC133 256MB SODIMM

    I've been told that this G3 can't use PC133 memory..and that I should use PC66.

    However, I had always thought that the faster SDRAM memory modules (excluding the newer DDR, of course) were *backwards* compatible.....

    Is it possible that this in fact *not* true..and that I simply have to use PC66 memory (or possibly PC100, as suggested by's memory selector)??

    What are your thoughts?

  5. MoparShaha macrumors 68000


    May 15, 2003
    San Francisco
    Are you sure it's actually a 256 MB chip? I've heard stories of RAM sometimes being mislabled accidentally. See if you can stick it into another machine to verify its capacity.
  6. AdamR01 macrumors 6502

    Feb 2, 2003
    Memory is supposed to be backwards compatible from what i know, but that is not always the case. An eMachines i worked on would not recognize PC133 but worked just fine with PC100. A Gateway I worked on recognized the PC133 but would bluescreen in windows. If I put that 133 stick in there alone it wouldnt POST. PC100 worked fine in that one as well.

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