Mac Pro Fan Speed / Heatsink Temp Issue

Discussion in 'Mac Pro' started by KBS756, Mar 18, 2013.

  1. KBS756 macrumors 6502a

    Joined:
    Jan 27, 2009
    #1
    Hey everyone, I upgraded my Mac Pro earlier this year until now I hadn't been gettin any issues, but now when I push it randomly (Not every time but here and there) I get the cpu a heatsink measuring a 120 C temperature for a split second, and then the fans go berserk and refuse to back down. During this my CPU Temps are normally reporting around 50 or 60 C.

    Would anyone happen to know what could be causing this?

    Once the fans start going they just don't back down unless i turn off the computer. The heatsink is supposed to cool the cpu which is the heat source so it shouldnt be radically high in comparison to the cpu even for a split second should it?

    Can anyone help me figure out whats going on here? Thanks!

    Thanks!
     
  2. bearcatrp macrumors 68000

    Joined:
    Sep 24, 2008
    Location:
    Boon Docks USA
    #2
    If you changed the processors to a higher ghz, doubt the firmware realizes it and maintains the spec of the lower processor. When I upgraded my mac pro 1,1 from quad to octo, had to bump up the fans a bit to compensate. To spike would indicate a program maximizing your cores for a brief time. When is the last time you blew out the dust bunnies? Doesn't take much to raise the temps. Might want to watch activity monitor to see if it is spikes from a program.
     
  3. KBS756 thread starter macrumors 6502a

    Joined:
    Jan 27, 2009
    #3
    I have a fan app in place to compensate for that. What I am experiencing is quite odd. The fans just refuse to back down once they spin up to max even if I close every program and leave it there for 20 mins.

    Also this is using less then 5% of my computers power sometimes the spike in speed rarely corresponds to much, it happens more often when pushed but just randomly otherwise
     
  4. bearcatrp macrumors 68000

    Joined:
    Sep 24, 2008
    Location:
    Boon Docks USA
    #4
    Would watch activity monitor after you shut down all programs to see if something is running in the back ground. Indexing is one such program.
     
  5. KBS756 thread starter macrumors 6502a

    Joined:
    Jan 27, 2009
    #5
    I honestly think there is some software or hardware defect causing this. I am rendering out a 3d scene right now using 2350% of processor or all 24 virtual cores almost maxed, and my CPU temps dont exceed 70 C and my fans remain reasonably low. While at other times Ive had it maybe using 1 core 100% and another 50% (like 6-7% of total system power) and have it mysteriously decide that it needs to be going full speed and then just stay there no matter what, with nothing showing up in activity monitor
     
  6. bearcatrp macrumors 68000

    Joined:
    Sep 24, 2008
    Location:
    Boon Docks USA
    #6
    When only one core runs, the turbo will ratchet up the processor higher than when many run. Could be a indicator the thermal past on cpu A needs replacing. When your rendering, watch your temps on both to see if any differences. If more than 10-15 degrees difference, might want to redo the thermal past.
     
  7. KBS756 thread starter macrumors 6502a

    Joined:
    Jan 27, 2009
    #7
    Not to drudge up an old thread but my processors have about a 10 Degree Celcius gap in temperature, should I assume something is wrong?

    IDLE CPU A 48 C CPU B 38 C

    Max Load (hrs of active rendering over 2350% usage CPU A 77 Degrees C CPU B 65 Degrees C)

    I am wondering if this gap in temperatures is normal with both of these CPUs X5680s Are these normal ? Thanks

    also for some reason my idle fan speed is at 2000 rpm in the heatsinks vs 1100 before. Is this normal for dual x5680s?
     
  8. Tesselator macrumors 601

    Tesselator

    Joined:
    Jan 9, 2008
    Location:
    Japan
    #8

    Yes, it's normal that one is a little hotter than the other. It has to do with air-flow (pathways and temperatures).

    2,000 RPM at idle sounds high to me but I don't have 1st hand experience. It's probably a little loud but I believe those cans can do 3,000 or 3,500 RPM so it's within spec. Under 50˚C (specifically 38˚ ~ 48˚) is typical for idle temperatures.
     
  9. KBS756 thread starter macrumors 6502a

    Joined:
    Jan 27, 2009
    #9
    Thanks

    I wish Idle speeds were a little lower, but other than that It's reassuring to know that the temperatures I have arent abnormal.
     
  10. Tesselator macrumors 601

    Tesselator

    Joined:
    Jan 9, 2008
    Location:
    Japan
    #10
    Sure, NP. The 120˚C you mentioned is not good tho.

    Your processor has a TCASE Max Operating temperature of 78.5°C and it's one of the few Xeons I've looked at that doesn't have TMT built in.


    So do be mindful when you're crunching numbers and such. I would install one of the fan controllers if it were me.
     
  11. KBS756 thread starter macrumors 6502a

    Joined:
    Jan 27, 2009
    #11
    I've determined the 120 reading was something wrong with the heatsink's temperature sensor because I reinstalled the heatsink and tried a ton of stress tests and never had it come up again

    the max my processor seems to get to is 78 C with the fans spinning at 3950 rpm

    with my 2nd processor at 68 C
     

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