11 Replies Latest reply: Feb 18, 2012 8:34 AM by DizzyDown
ThatsUnpossible Level 1 (0 points)

I purchased a new 2011 iMac with the i7 quad core 3.4ghz processor.


A few days after owning it, the display started acting very strangely. The nearby Apple store replaced the machine since it was within 14 days.


With this new one, I can hear the fan going, all the time. Much more noticeable than my previous iMac (a 2009 model I believe), and more noticeable than the other 2011 iMac we bought with the i5 3.2ghz processor.


It's not running at full speed or anything, I don't even necessarily think it's running when it shouldn't be -- it's just louder, to the point where I actually notice it, when I never did on previous iMacs unless something was wrong.


Is anyone else experiencing this?


I just hate to take this second iMac over to the Mac store if it's just "how it is."



  • Mike_Morgan Level 1 (10 points)

    I have the upper 21" model and have noticed it too, but honestly it's a welcome relief for me. My previous iMac would get so friggin hot because Apple wanted it to be "whisper quiet" that it would often just shut itself off. I told myself many times that I would rather have a machine with audible fan noise and know that it was being cooled properly than worry about how long I could play a game before it shut off. Plus these machines are more powerful so it makes sense that they had to improve the cooling system.


    Incidently, the first one I bought had some Airport issues so I took it in four days later and they swapped it for a new one. I noticed the louder fans on that one too, so I have to think that this is "how it is", and about time, too.

  • WZZZ Level 6 (12,855 points)

    Get iStat Pro free widget and post the fan speeds and temps.



  • ThatsUnpossible Level 1 (0 points)

    Good advice. OK, here are the stats:


    Fan speeds:


    Optical drive: 999rpm

    Hard drive: 1098rpm

    CPU fan: 940rpm


    Temperatures (Fahrenheit):


    HD: 85º

    CPU: 86º

    Ambient: 61º

    GPU Diode: 108º

    GPU Heatsink: 97º

    Mem Controller: 94º

    Optical Drive: 83º

    Power supply 2: 104º


    Any way to know if these are all normal?

  • John Kitchen Level 3 (645 points)

    Those temperatures are way, way below the danger zone.  What happens when you drive the CPU workload up for a long time?

  • John Kitchen Level 3 (645 points)

    Another thought is that at those temperatures, you may well be getting Turbo Boost to kick in and improving performance.  It's not huge but 3.4GHz rises to 3.8 on the i7.  Turbo Boost won't kick in if the temperatures are high.

  • ThatsUnpossible Level 1 (0 points)

    John Kitchen wrote:


    Those temperatures are way, way below the danger zone.  What happens when you drive the CPU workload up for a long time?


    I'm a little confused by the question, the issue I am having is that the fan is more audible than expected at idle. It definitely doesn't sound like it's running really loudly, as I've heard (usually from my macbook) when the CPU is working hard.


    I've tried hitting the CPU just now by running "yes > /dev/null" in 8 different terminal windows at once. It pegs out the CPU in activity monitor at 100%, though the system is still completely responsive. All of the temperatures (except Ambient) are up above 100º and many are above 120º. CPU is now at 144º. Ambient sits at 68º.


    The fan speeds remain as they were, almost exactly. I'm guessing because the ambient temp hasn't gone up that much.


    A few minutes have passed, CPU is at 150 and so is Power Supply 2. Ambient remains at 68º. (Guess those "loud" fans are working ;-)

  • WZZZ Level 6 (12,855 points)

    I don't know exactly what the defaults are for your model, but those fan speeds, at least the ones you posted, look like they're idling at the defaults.

  • ThatsUnpossible Level 1 (0 points)

    OK thanks for the feedback!

  • John Legenhausen Level 1 (10 points)

    I have the same issue with same model. If the noise is normal I'm ok with it but it would be nicer if this iMac were as silent as my old 24 inch model. Did you do anything about determining if the noise level is normal?

  • Hawaiian_Starman Level 7 (21,405 points)

    Might be helpful to reset the System Management Controller.




    Shut off the computer. Unplug it. Press/hold the power button for 5 seconds. Plug-in, then restart.

  • DizzyDown Level 1 (10 points)

    are you sure it's not a hard drive? if you hear how it's spinning up after power on or sleep and then the noise starts - it's a hard drive. they are too much noisy in 2011 iMacs. my 2 TB drive is incredibly noisy at idle.