Troubleshooting G5 CPUs

Discussion in 'PowerPC Macs' started by Zeke D, Aug 5, 2012.

  1. Zeke D macrumors 6502a

    Zeke D

    Nov 18, 2011
    Many of you know I am having trouble with my G5. I want to rule out the CPUs. What will happen if I put a pair of 1.8Ghz CPUs in there? I know the 2.0 runs at 1000Mhz, and the 1.8s run at 900Mhz FSB. Will the 1.8s still work , lowering the FSB of the system to 900Mhz? or will it just fry my logic board?
  2. Mengele macrumors member

    Aug 6, 2012
    It won't boot. G5 logicboards are CPU specific. Even just switching the existing CPUs A-B B-A will cause the cooling system to run at full speed all the time.
  3. bengi macrumors member

    Jul 21, 2011
    that's true because you then need to recalibrate the sensors. there's a specific software, which is a nightmare (it works 1 out of 5 CPUs).

    however the question is still valid, wht are PowerMac G5 logic boards considered CPU specific?

  4. havokalien macrumors 6502a


    Apr 27, 2006
    Kelso, Wa
    CPU motherboard

    The bus speed is set and is half the speed of the CPU. A faster CPU may work but not usually, and will not boot the other way. The ASD ( apple support disk ). 2.5.8 for 1.6 to dual 2.0.

    Good luck

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