Powermac g4 350 maximum memery?

Discussion in 'Apple' started by Evan Platt, Jul 21, 2006.

  1. Evan Platt

    Evan Platt Guest

    I have a secondhand Powermac g4 350.. I have a 512 mb stick, a 128,
    and a 64. Granted it runs fine on 512, but the 170 would be helpful.

    It only recognizes the 512 - even with the 128 and 64 and 512, it says
    512 megs free.

    I haven't yet tried just booting with the 128 and 64. But am I missing
    anything obvious? Yes, they're all different speeds I'm sure.


    Evan Platt, Jul 21, 2006
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  2. Evan Platt

    David Empson Guest

    Does your PowerMac G4 have PCI graphics (Yikes) or AGP graphics
    (Sawtooth)? I expect it is a Sawtooth.

    Both models have four RAM slots and take PC-100 DIMMs, but the PCI
    Graphics model has a maximum of 256 MB per slot (1 GB total) and the AGP
    Graphics model has a maximum of 512 MB per slot (2 GB total, but Mac OS
    8/9 can only use 1.5 GB).

    The AGP model is slightly fussier about the RAM which can be used.
    Mixing sizes isn't a problem, nor is mixing precise speed specifications
    (e.g. "333" vs "222" access cycle timing).

    You need to have memory which is fully compliant with the PC100
    standard, and doesn't have unusual features like buffering or parity.

    PC133 will work, but won't have any speed benefits. PC66 or slower will
    not work.

    The memory must implement the serial presence detect EEPROM, which
    allows the computer to identify it and determine precise timings.

    Some generic cheap RAM is missing this, or it isn't programmed
    correctly, preventing the RAM from working in a Mac.

    This program from Glenn Anderson might help if the issue is just that
    the SPD EEPROM hasn't been programmed. It must be run while booted into
    Mac OS 9. <http://www.mactcp.org.nz/dimmfirstaid.html>

    Some DIMMs might have the memory arranged in a way which is not
    supported by particular Mac models. Here is a note from Glenn's DIMM
    First Aid page:

    Incompatible 256MB and 512MB DIMMs: 256MB DIMMs made from one bank of 16
    32Mx4 chips and 512MB DIMMs made from one bank of 16 64Mx4 chips are not
    compatible with the G4 AGP Graphics, the slot loading iMac, and later
    models of Mac. They will only work in the Beige G3, the B&W G3, and the
    G4 PCI Graphics. If you are buying a 256MB or 512MB DIMM and you are not
    sure if it will work on a Mac, do not buy DIMMs that have a single bank
    made from 16 chips, make sure it has two banks of 8 chips each, or for
    256MB DIMMs one bank of 8 chips or two banks of 4 chips are also OK.
    Incompatible DIMMs may also be identified as having 32Mx4 chips (for a
    256MB DIMM) or 64Mx4 chips (for a 512MB DIMM). DIMM First Aid will
    identify these DIMMs as having an incompatible number of column address
    bits. DIMM First Aid can not fix these DIMMs.
    David Empson, Jul 22, 2006
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