8 month old 27" iMac running WAY too hot, fans not spinning up

Discussion in 'iMac' started by ksgant, Nov 13, 2012.

  1. ksgant, Nov 13, 2012
    Last edited: Nov 13, 2012

    ksgant macrumors 6502a


    Jan 12, 2006
    Why is it that I can't ever get a Mac to spin up fans as the load on the CPU goes up? My 8 month old, bought brand new, 27" i5 iMac has no fan spin up even under heavy load.

    I've reset the SMC on this new iMac, have no 3rd party "fan control" software running at all, and yet the CPU fan sits there at 939 RPM (according to istat menus) while ffmpg is converting a video and has all 4 cores pegged at 391% and the CPU temp is up to 66 degrees celsius when sitting idle it's at 35-39 degrees or so.

    While yes, I could install 3rd party fan control software, why should I have to? Why shouldn't this iMac regulate it's fans right out of the box?
  2. macking104 macrumors 6502


    Jan 14, 2003
    California, USA
    Instead of whining on this site, you may want to contact Apple for technical help/service...
  3. simsaladimbamba

    Nov 28, 2010
    66° C is an acceptable temperature for a desktop i5 CPU, there is no need for the fans to spin faster.

    My 2007 C2D Aluminium iMac's CPU can go up to 70° C or so, and the fans are still spinning at their base speed, but then again, it is a C2D and I do not have an aluminium back like the i5 and i7 iMacs, thus heats does not dissipate as good.
  4. ksgant thread starter macrumors 6502a


    Jan 12, 2006
    First, I've gone to their forums over there and asked. But I've already gotten a response here. Albeit one was useless, the second one was helpful at least.

    Second, I wanted to get some opinions to see if this is normal or not or just an issue with my one computer before contacting Apple directly.

    Third, why even respond to this if you're not helping? I mean, could you elaborate more about if I should contact Apple or not for technical help...sitting on a phone forever or waiting at a Genius Bar if this isn't a problem? If you're intent was just to complain that I'm "whining", then just move on.
  5. Siderz macrumors 6502a

    Nov 10, 2012
    Like other people have said, this is perfectly normal.

    I think the fans will speed up once it hits 70°C.

    If you really want the fans to go faster, download smcFanControl.

    It's unlikely that it'll break your computer, but if you ever take it to the Apple Store you will need to uninstall it first otherwise the people there will refuse to help you.
  6. joe-h2o macrumors 6502a

    Jun 24, 2012
    "Way too hot" does not describe 66ºC on an i5 CPU. The fans aren't spinning up because the CPU is still well inside its normal operating range. I believe the "whoa, bro, time to seek shade!" limit on the i5/i7 is over 70ºC.
  7. Yeroon macrumors member


    Jun 12, 2012
    The fans of my Macbook Air spin up when the chips reach 100 degrees Celsius, so no need to worry. Unless you say that your iMac used to make more noise in the past.

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