Is my iMac overheating

Discussion in 'iMac' started by Barbatian, Jul 1, 2017.

  1. Barbatian macrumors newbie

    Jul 1, 2017

    as the titles says I have late 2015 27iMac. I have also boot camp installed with Win 10 I noticed that temperatures on windows at almost idle stance reach above 80C for CPU and GPU. When started a game GPU and CPU went even 107C!!

    While on Mac OS temperatures idle are around 50C even below.
    I did a stress with "yes" excercise and stressed CPU's to around 90% of total resources.
    I was looking at temps and CPU never crossed 100C was around 95-100C.

    1. Are these 100C temps on MAC OS full stress ok or is my Mac overheating?
    2. If 1 is ok, is this normal on Windows OS or it is damaging?
    3. if 2 is not ok, do you have any ideas how to solve it (I know maybe it's not right place but...)

    Barb Screen Shot 2017-07-01 at 12.15.15.png
  2. EugW macrumors 601


    Jun 18, 2017
    Is your CPU the i7-6700K? Tj Max is supposedly 100C from what I understand for the i7-6700K, although I’m not sure because the usual specs from Intel don’t list it for the 6700K. It’s 100C for the 7600K and 7700K though.

    Assuming your CPU is the i7 and assuming that is core temp then yes, the 107C in Windows is too high. Should be 100C or lower. However, I’m not sure why it’s not throttling more then.
  3. Barbatian thread starter macrumors newbie

    Jul 1, 2017
    Hello EugW,

    thank you for you quick reply.
    Yes, my CPU is the i7-6700K. I run the test multiple times and never crossed 100C.
    I cleaned backside with vacuum and now Idle temps went to low 40C.

    I was a liitle mistaken with my statement.
    I have Radeon R9 395X and the GPU temp was 107C on Win 10. I will try to do GPU test on MAC, to see what;s happening.

    Morevoer on Win 10 by 85C fans do not increase speed at all. It's quite the same as MAC OS 50C.
    The fans start raising at around 90C+. On MAC it's much different.
  4. EugW macrumors 601


    Jun 18, 2017
    Ok that makes more sense. The CPU should never be above 100C.
  5. Barbatian thread starter macrumors newbie

    Jul 1, 2017
    I just did a test for GPU on MAC.
    I was quite happy it didn't go beyond 100C but...
    The fans were around 1500-2000 and didn't raise.
    I increased fan speed with Macs Fan Control to 2750 and the temp went to constant 93-94.
    Then set to auto and temp went again 99-100C

    Why Mac is not speeding up fans when GPU goes 100C?

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