iMac 2011 GPU temps high in Lion.

Discussion in 'iMac' started by fredou, Aug 14, 2011.

  1. fredou macrumors newbie

    Joined:
    May 21, 2011
    #1
    This is what I get for the GPU after playing 10 minutes of a simple card game. (88C) I can't imagine what it could be playing an FPS Game. This is on an imac i7 2011. I never had any such high temp before in SL. I would say 75C max in SL running extensive GPU benchmark during an hour. Now only 10mins and I got something way too high. I know imac could handle high temp, but I'm not so sure about this one for a long time without damaging something.

    Have you guys got such high temp on the latest imac?
     

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  2. Spike88 macrumors 6502a

    Joined:
    Jan 25, 2010
    #2
    Yes. The new 2011 iMac "run hot" under load. Especially with current version of Lion. This can be seen by performing Google Search using "2011 iMac hot" search string.

    --------------

    Found an interesting item.

    re: AMD 6970 - 2 GB GPU in "open air" enironement "under" load rises to 54C.

    For more details, surf bottom chart @ http://www.bit-tech.net/hardware/graphics/2010/12/15/ati-radeon-hd-6970-review/10

    Based on their 54C "peak" number, me thinks there's too much video card packed under too tight of physical space (within the iMac chassis).

    Suggest installing 3rd party Fan control software (like SMC Fan Control 2.3) and increasing fan speed by 400 RPMs above their recommended default. Specifically its Optical drive fan speed, which also keeps its GPU cooler. Cooler GPU the better.

    Hope this helps in your research...
     
  3. thegoat macrumors newbie

    Joined:
    Aug 6, 2011
    #3
    The iMac uses the 6970m, the link you provided shows the 6970 (for desktops)
     
  4. Spike88 macrumors 6502a

    Joined:
    Jan 25, 2010
    #4
    6970M info at:

    http://mobile4mee.blogspot.com/2011/01/amd-radeon-hd-6970m-graphics-card.html

    http://images.anandtech.com/doci/4223/Clevo P150HM HWMonitor.png


    I'm sure other 6970M "heat chart" info can be found using google search.

    As seen within these above links, the GPU heat range is between 40 - 80C. 50s-60s is probably its sweet spot - within open box environement.

    As seen within the "slim case" of the iMac box, the heat is trapped inside it. Everything runs hot within a thin box. Thus, its "under load" heat is much higher - compared to open box design. Into the high 80s/90s. If I remember correctly, someone one posted that an iMac has an emergency "shut down" (from heat over load) at 100C. If that's true, it means very little temp variance - from its under load temps to emergency shut down. No wonder why many folks are complaing the top of their iMac is extremely hot. It's starving for air flow.

    As stated above, install SMC Fan Control (or some other 3rd party fan control software), crank up the fan's and additional 300 or 400 rpms (which is very little increase) and watch its inner temps go down. Its amazing to watch its inner temps go down - as the fan speed increases only a small 300 rpms...

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