Mac pro 5,1 fan running high PCI & PS

Discussion in 'Mac Pro' started by cpnotebook80, Feb 20, 2017.

  1. cpnotebook80 macrumors 6502a

    Feb 4, 2007
    Just noticed that the fan runs loud and constantly when I open a browser like firefox or safari. So I installed macs fan control. See attached.

    The PCI and PS(Not sure what PS is.?) seems to be running high for some reason and then slows down. I have OSX sierra. The main OSX is on a pcie ssd.

    The graphics card is an amd 7950 and is the only graphics installed. See attached image of what I see in the system report.

    The fans are quite now but they do run high when you open browser or some small app. not sure if i have to be concerned.


  2. owbp macrumors 6502a


    Jan 28, 2016
    Belgrade, Serbia
    @Filin I think that is the case with nVidia GPUs only.
    I've had 3 HD79xx cards (two 7950 and one R9 280X I still own) and never had similar issue.
    PCI and PS fans are ramping in my Mac when GPU is under load and hot, but 25˚C for PCIE Ambient is far from hot.
    Screen Shot 2017-02-20 at 9.11.39 PM.png
    You can see my PCIE Ambient with two monitors connected. When I connect only one, it goes down to 30-32˚C and PCI Fan goes back to 800RPM.

    @cpnotebook80 , Im almost positive that rivet has snapped on your Northbridge heatsink.
    But I don't think that is causing any problems you have.

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