iMac G3 detects 256MB RAM stick as 128MB

Discussion in 'PowerPC Macs' started by Daniël Oosterhuis, Jan 14, 2016.

  1. Daniël Oosterhuis macrumors 6502a

    Daniël Oosterhuis

    Joined:
    Jan 10, 2016
    Location:
    Black Mesa Research Facility
    #1
    I recently bought a second hand low profile 256MB PC133 RAM stick for my Bondi Blue iMac G3, which was running on 96MB (32MB+64MB). I took out the 32MB stick today, and replaced it with the 256MB one. Booted the machine up... it only registers it as a 128MB stick? Swapped places with the 64MB stick... nope. I think this is the Rev. B model (6MB of VRAM), but even if it were the Rev. A, it should detect the 256MB stick fine. What's going on here? Is this a known issue? Is the 64MB messing with it?
     
  2. T'hain Esh Kelch macrumors 601

    T'hain Esh Kelch

    Joined:
    Aug 5, 2001
    Location:
    Denmark
    #2
    THe machine can only use 256MB sticks in the second slot I believe. The first one only supports up to 128 MB sticks, for a total and unofficial, support of 384MB. So in essense, just swap the chips currently in the machine.
     
  3. Daniël Oosterhuis thread starter macrumors 6502a

    Daniël Oosterhuis

    Joined:
    Jan 10, 2016
    Location:
    Black Mesa Research Facility
    #3
    As I mentioned, I have already tried both the RAM slots, the one on the bottom of the CPU card and the one on top. Both detect it as 128MB. It's an Infineon Low Profile 32x8 PC133 256MB module.
     
  4. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #4
    It's a Rev. B, which should take a total of 512mb.

    You need LOW DENSITY RAM for this model. Search for DIMMs with 8 chips per side(16 total). They are available out there in "normal" length(not the huge Apple sized ones). You don't NEED PC133(PC100 or PC66 will work fins) so search for these speeds to broaden your net a little bit.

    I went through the same thing a few months back maxing out the RAM in my Powerbook G3s. The first round of 256mb sticks I bought only registered as 128mb, so I went hunting(and found on Ebay) the 16 chip 256mb ones.
     
  5. Daniël Oosterhuis thread starter macrumors 6502a

    Daniël Oosterhuis

    Joined:
    Jan 10, 2016
    Location:
    Black Mesa Research Facility
    #5
    Isn't 32x8 low density? Or do I need even lower?
    I was aware that the speed doesn't exceed the PC66, however this stick only costed me €2,50 shipped to my mailbox, so it's not much of a loss. Having some RAM as a back up can't hurt after all.
     
  6. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #6
  7. California macrumors 68040

    California

    Joined:
    Aug 21, 2004
    #7
    And I owned a couple of those Bondi Blues, one with the lower Vram and the 6vram and got both up to 1 gig total in ram . Ignore the 512mb limit set by Apple; with the correct ram they can run 1 full gig of memory.
     

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