Mac Pro running hot after 12-core 4,1--> 5,1 upgrade...

Discussion in 'Mac Pro' started by PowerMac G4 MDD, Mar 8, 2017.

  1. PowerMac G4 MDD macrumors 68000

    PowerMac G4 MDD

    Joined:
    Jul 13, 2014
    Location:
    At the intersection of Conch and Coral.
    #1
    So, it appears that my machine is running pretty hot with this upgrade. It has been over a month since I've done the upgrade, and everything was fine in the beginning. In fact, my machine was reporting better CPU temperatures then.

    Now, however, the CPU temps are up - and, most importantly, the Northbridge chip (the chip itself - not the heatsink) is currently resting at a hot 169F, with fans all at default speeds. Ambient air is 88F, and room temperature is ~75F. I am not seeing anything unusual or resource-intensive running. Additionally, a while back - while still at eight cores - I cured my Nb chip of its overheating issue, by replacing its plastic pegs and giving it new thermal paste. Still seems hot, though...

    What are your temps for your 12-core classic Mac Pros? I'm curious to see. These temperatures don't look normal. The Nb chip temps were higher from the start, but now my CPU A diode is at 120F with a few applications open.
     

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  2. PowerMac G4 MDD, Mar 8, 2017
    Last edited: Mar 15, 2017

    PowerMac G4 MDD thread starter macrumors 68000

    PowerMac G4 MDD

    Joined:
    Jul 13, 2014
    Location:
    At the intersection of Conch and Coral.
    #2
    EDIT: I resolved this myself, and I hope that anyone who has the same question will have it answered here.

    This sounds cliche and obvious, but I believe it was dust + the location of the PC. I knew that my machine was a bit dusty, but I had no idea how much the dust and location of the tower were actually affecting its thermals. Typically, a machine can have its fans and heatsinks completely blocked by dust, and they will still run fine. However, with only moderate amounts of lint, mine was not getting the proper cooling that it needed. Also, it was on the ground, behind my desk. I guess that's not a big deal, as my temperatures were fine for a while. However, it seems to have been the dust down there that got to it.

    I dusted out everything (including the heatsinks), put the Mac up onto my desk, and am now typing this with a CPU A diode temperature of 104-106F, and a Nb chip temperature of 153F. A very nice improvement! I'm down more than 10F on each of those. Ambient air temperature can be contributing, of course, as it's now 81F instead of 88F. So, looks to have been a combination of dust and computer placement.

    I only disregarded dust because whether or not I've dusted out a computer usually doesn't make a difference for me. Anyway, now to run more things and see what happens.
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