CPU temp 100°C+, fan still at 2000RPM

Discussion in 'MacBook Pro' started by Transporteur, Mar 14, 2010.

  1. Transporteur macrumors 68030

    Joined:
    Nov 30, 2008
    Location:
    UK
    #1
    Hey there
    I've notices a really strange behaviour with my 13" MBP. The fan simply doesn't go faster on high loads, which results in a CPU temperature that is far beyond the operation specification Intel provides.

    Seems as if the SMC controller is kind of broken. I tried to reset it, but that didn't change anything. A PRAM reset also didn't work.

    How can I fix that?
     
  2. Eidorian macrumors Penryn

    Eidorian

    Joined:
    Mar 23, 2005
    Location:
    Indianapolis
    #2
    I'd be a little more patient for a spin up. It's pretty standard operation otherwise.
     
  3. Transporteur thread starter macrumors 68030

    Joined:
    Nov 30, 2008
    Location:
    UK
    #3
    100°C is deadly and far from standard! Keep in mind that the 100° are read from the heatsink, so you can probably add another 10-15° for the core temp. Intels maximum core operating temperature is somewhat around 90°C. With a proper cooling solution and normal ambient conditions, the chip should never go over that value as it reduces its lifetime dramatically.

    When I got that machine the fan got to 5000RPM+ even at 70°C, so there is definitely an issue with the fan controller.
     
  4. Eidorian macrumors Penryn

    Eidorian

    Joined:
    Mar 23, 2005
    Location:
    Indianapolis
    #4
    105° C for the P8400.

    Are you waiting around for the fans to spin up? Be a little more patient. Apple doesn't want the fans spinning up from idle for a few seconds of heat.
     
  5. Transporteur thread starter macrumors 68030

    Joined:
    Nov 30, 2008
    Location:
    UK
    #5

    Higher than I remembered. :eek:

    You are right Eidorian! I waited a little longer and finally, after 8 minutes, the fan spun up to 5000RPM.
    Still the reported temperature was way too high, so I ended up re-installing iStat.
    My temperatures are way lower now and the fan spins up at 70° again.

    So the book was fine, only iStat reported false values.

    Thank you very much Eidorian!
     
  6. Eidorian macrumors Penryn

    Eidorian

    Joined:
    Mar 23, 2005
    Location:
    Indianapolis
    #6
    It's alright. I hope I wasn't too hard on you about this subject. It's a rather common one.

    Software is going to poll the temperature sensors and you can even go down to the diode. There's a certain level of variance nonetheless. It's going to save itself if you're in real danger. You're also under warranty. ;)
     
  7. Transporteur thread starter macrumors 68030

    Joined:
    Nov 30, 2008
    Location:
    UK
    #7
    Doh....!
    Should have used the search function a little more thoroughly. :eek:
     
  8. Eidorian macrumors Penryn

    Eidorian

    Joined:
    Mar 23, 2005
    Location:
    Indianapolis
    #8
    I'm glad I was able to help you. Be glad that your experiences and this thread are going to help the next person that asks this question.
     
  9. ayeying macrumors 601

    ayeying

    Joined:
    Dec 5, 2007
    Location:
    Yay Area, CA
    #9
    It reads the diode temperature, not the heatsink. Big difference there.
     
  10. elektralv macrumors newbie

    Joined:
    Apr 14, 2008
    #10
    MBP fan control

    There is a great system preference that lets you control fan speed. It's called "Fan Control" and can be downloaded here.
    http://www.lobotomo.com/products/FanControl/
    I set the idle speed up to about 3000 which helps keep my 3yr old MBP cooler.
     

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