G5 Logic Board Switch

Discussion in 'PowerPC Macs' started by blevesque14, Apr 13, 2011.

  1. macrumors newbie

    Apr 13, 2011
    Hey Guys,

    I have a Power Mac G5 that the logic board is dead in. It is a 1.8 ghz Dual Processor. My question is if I'm going to replace it do I need to put the same "matching" one back in. Or can I put any dual processor back in. Does the board change from the 1.8 to the 2.5ghz? I know some of them have the liquid cooled heat sinks. Plus my understanding is the processor is what determines the ghz not the board. Any help would be appreciated. Thanks in advance. B

    Oh maybe you might want the logic board number to understand what I have a little bit better. (I just feel that a G5 case is a G5 case and it should accept any board i put in?!)

    KD4065Q9QEJE 630 4914 630T4918
  2. macrumors member

    Mar 21, 2011
    Assuming that the processors aren't dead, then you should be able to get a new board on ebay or another site and install it. You are correct where the board does not determine the clock speed. If you also want to boost performance you could buy new G5s on ebay and install them on the new board. Good Luck!:eek:
  3. macrumors member

    Apr 17, 2011
    That is false information. The logic board is programmed to a specific bus speed which is tied to CPU speed. It also has the CPU serial stored, even swapping the same cpus to opposite lots will make the computer go into safe mode (full fan speeds).

    Changing a CPU or logicboard requires matching part types, and any change requires thermal recalibration.
  4. macrumors 6502


    Mar 12, 2011
    Somewhere in Cyberspace
    Why not just get a dual core G5 or even the last model G5, the G5 Quad? By the time you get the logic board and possibly new processors, you would have exceeded even a G5 dual core or Quad.
  5. macrumors 65816

    cherry su

    Feb 28, 2008
    You have to put identical processors in DP systems. I don't think a single core 2.5GHz and a dual core 2.5GHz will work. However, I think you can run it with only one processor. (DP x86 systems work this way)
  6. macrumors member

    Apr 17, 2011
    Nope. The G5 models share nothing whatsoever in common with PCs except the expansion slots and drive interfaces.
  7. macrumors 601


    Sep 16, 2007
    Northeastern Ohio
    Some of the processors will work with different boards. I've swapped CPUs around with different boards and not all of them worked with another. You can run a single processor on a dual processor board as long as it's in the upper slot. Swapping processors or Logic boards will require a thermal calibration. Do you have the Apple Serivce Diagnostics discs?

    You should be able to use any 1.8ghz or 2.0ghz dual processor logic board. Make sure it has the same amount of memory slots.
  8. macrumors 6502


    Sep 9, 2006
    Aurora, IL
    I've swappd several and as long as you are the same family (970 vs 970fx) you should be ok

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