27" iMac overheating

Discussion in 'iMac' started by iGrainger, Jul 11, 2011.

  1. iGrainger macrumors member


    Aug 31, 2010
    Hello guys,

    I got my iMac today, and I really do love it, but it's overheating like crazy, even when just browsing the web or watching a film. It's VERY VERY hot, and I'm sure others have had this issue before now, but I wanted to address it and see what it is, and if it's normal and or what to do!

    Many Thanks in advance!
  2. basher macrumors 6502


    May 27, 2011
    Glendale, AZ USA
    Is the iMac so hot that it's shutting down?

    The case of the iMac is designed to act as a heat sink to wick away heat. My iMac gets how on the top and back sides.

    Is there proper airflow around the iMac? The mac sucks in air from the bottom and blows out some hot air from the slot on the top of the unit.
  3. iGrainger thread starter macrumors member


    Aug 31, 2010

    I've only had it today, so far no issues, no forced shutdowns, nothing, I just noticed that the top of the iMac is rather hot at times, and so is the sides. The bottom is quite cool.
  4. dgr macrumors member

    Jun 24, 2011
    I played Borderlands for a few hours and although it gets hot in the back it has never caused an issue. I noticed at the Apple store it did this as well so I assumed it was normal.....I didn't know it acted as a heat-sink....pretty cool (pun intended). ;)
  5. omvs, Jul 11, 2011
    Last edited by a moderator: Jul 17, 2011

    omvs macrumors 6502

    May 15, 2011
    Yeah, the top will get rather hot - especially under load/gaming. Even idling my top gets warm enough that you wouldn't want to hold the top without letting it cool first, but the internal temps (as reported by iStat pro) are very reasonable. I believe this is because hot air is ejected from the top and sucked in from the bottom....

    If you can't hear the fan going, you're probably okay. I can barely hear my fan when gaming (spins ~1500-1600rpm), and not at all when its idle (spins ~1000rpm)
  6. iGrainger thread starter macrumors member


    Aug 31, 2010
    Hey guys,

    Just wanted to say thanks for the tips and the quick replies. Was slightly worried, especially as it's my first day with the machine. If the heat isn't just with me, then it's fine. I was just hoping my iMac wasn't faulty or had an issue with heating/fans.

    I've downloaded iStat and nothing seems out of the blue or unordinary high at least.

    Thanks again for the help.
  7. pilkenton, Jul 11, 2011
    Last edited: Jul 11, 2011

    pilkenton macrumors member


    Mar 30, 2011
    My Mac was always hot. I figured it was normal, but on a hot day you can fry an egg on the top of my Mac. I have a small desk fan blowing at the Mac from the side. It's quiet and barely blows, but my Mac stays cool all the time.
  8. Spike88, Jul 11, 2011
    Last edited: Jul 11, 2011

    Spike88 macrumors 6502a

    Jan 25, 2010

    It's the inner (not the outer) temps that one should focus on. Heat flowing out the top of the iMac could be a great thing (intead of this heat remaining inside).

    With this in mind, recommend downloading iStats Nano (which is a free widget) and check the internal temps. And, ensure the fan speeds (all fans) are working properly as well. And, to get samplings of inner temps. Especially when iMac is under different loads.

    If it runs "too hot when under load" for your comfort feeling, I would download (and buy for $16.00) iStats Menu 3 utility and customize your iMac internal fan speeds. For example, set at mininum speed somewhere between 1,200 - 1,800 RPMs. Keep "tweaking" the FAN speeds faster or slower each week until you find the right RPM - for your iMacs usage. One doesn't need to set the fans to "super fast". Only slightly faster RPM than factory default. Works for me...

    re: http://bjango.com/mac/istatmenus/

    IMO, the MacOS X should include little utilities like IStats Menu and iGlasses. But... that's a topic for different threads.

    Good luck....

  9. And1ss macrumors 6502a


    Oct 20, 2009
    I don't think you have anything to worry about. It's pretty standard for iMacs to get that hot.
  10. philipma1957 macrumors 603


    Apr 13, 2010
    Howell, New Jersey
    personally any owner of am imac should buy istats menu 3

    16 bucks to help protect a 2000 pice of equipment makes sense to me. if you wall mount your iMac you get nice air flow bottom to top. just keep the iMac at least 2 feet under the ceiling.

    Attached Files:

  11. RoyalFlushAK(s) macrumors member

    Jun 15, 2011
    protect the investment?
    what are you talking about? - if Apple would think an app like istats would be beneficial to the system, they would have programed inside the OS. Spending $16 for kids staff app is a waste. Using istats by trial and error figuring out different temps is "y##@^%^&*ugf" this lol, lol,

  12. Spike88, Jul 11, 2011
    Last edited: Jul 11, 2011

    Spike88 macrumors 6502a

    Jan 25, 2010
    Unfortunately, the iMacs isn't perfect. Especially when it comes to jamming more items into an already "too thin" all-in-on box. A few times, I remember reading about folks having several 2010 / 2011 iMacs, they all do the same work and using iState Nano (free widget), each of their inner temps are different. And, each of their inner fan speeds are different as well. Why is that so? Because not two exactly the same iMacs are eactly the same. Some sensors are slightly off. Some have hotter internal parts. I also get the feeling that Apple doesn't "over load" their systems with many public games or other inner taxing stresses. Thus, determining the full "real world" of "More load = more stress = more inner heat" outcome. A negactive side effect reality that many compuer Quality Control testers don't fully understand.

    IMO, iMacs are like today's automobiles. They are built / tested at normal loads. They are tested with "the average" expectations of that tool and for only short time periods. But just like automobiles, when pushed above normal loads (internal cargo or pulling an attached trailer), its transmission is over stressed, which creates more heat. To proactively eliminate "over heating / over cooking" the vehicle's insides, an aux ATF cooler is proactively installed. More proactive cooling - which saves the transmission from over cooking. To me, the iMacs are the same stress = heat comparison. Too much "load" and their insides are over stressed, which creates lots of heat. To proactively eliminate the heat, one installs "better then factory" cooling. re: 3rd party fan control program and configure it for that iMac's loads. Without "better than factory", the insides of the iMac over cook. And in time, its insides burn out. Just like an over cooked vechilce transmission burns out in time as well.

    If wondering, I installed 3rd party Fan Speed control software within my iMac. My iMac now runs 10-15 C lower. Yes. Lower than before. Lower than factory. All because I proactively take a better than factory attitude with my iMac. Sure. I could leave it "as factory". Drive it until it over cooks its insides and it auto shuts down. When it shuts down (just like a temp light in a vehcile), the damage is already done. Hence, why many people call it the "too late" safety switch. Or, "too late" dummy light.

    Do or do NOT install a 3rd party fan control software (and set it for your unique iMac or its unique loads). We each live in a free world. But... If one plans to keep their iMac for many years and plan to "load it down" (like my iMac), I too recommend 3rd party Fan Control sofware as well... Works for me...


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