Mac Pro Fan Noise after 4.1 to 5.1 UPGRADE

Discussion in 'Mac Pro' started by sagenumwoben, Jul 2, 2015.

  1. sagenumwoben macrumors newbie

    Feb 23, 2015
    Hamburg Germany
    Hey Guys,

    i got a problem. i did a 8-Core to 12-Core UPGRADE and now the Core A and Diode A is not showing up Temperature and speed in TG PRO or iStat.

    in System Monitor it shows up 2x 2.66 6-Core, everything works fine, but BoostA makes constant noise.

    PRAM and SMC Reset is done.

    nothing changed.

    TG Pro in manuall mode on and off.
    Screenshot from system manager.

    Attached Files:

  2. ActionableMango macrumors G3


    Sep 21, 2010
    A lot of things can cause fan problems, but the fact that you just changed the CPUs on a dual 4,1 model probably means you missed a step in the upgrade process somewhere. This problem comes up every now and then from people who upgrade the processors on the 4,1 MP dual CPU model.

    Read the following article all the way through, but here is some pertinent text:

    Each heat sink (there are two in 8-core and one in 4-core machines) contacts a socket on the processor board (daughterboard) when it is installed which conveys temperature data to the fans. This socket has to be modified to maintain proper contact (8-core machines only). Failing that the fans will roar up to full speed, some 5,200rpm – a welcome failsafe, maybe, but not one you want to hear all day.

    Note elsewhere in the article that the CPU isn't the only thing that contacts the heat sink:

    Additional thermal pad material will have to be added contacting this area for each heat sink.

    Note that CPU A and Heatsink A temperatures are missing in your screen shots. Basically, the heatsink isn't contacting the correct surfaces, so the temperature data isn't getting through, so the fans are operating at full speed.

    Good luck!

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