2014 imac fan running more often?

Discussion in 'iMac' started by xgman, Oct 27, 2014.

  1. xgman, Oct 27, 2014
    Last edited: Oct 27, 2014

    xgman macrumors 601

    xgman

    Joined:
    Aug 6, 2007
    #1
    My 2014 i74ghz 1tb ssd 295x imac's fan is kicking in (rather loudly) regularly at various times under medium load, far more than I ever heard the 2012 top end imac's run. It's not the end of the world, but in seems like it is coming on 10x more than the prior imacs. Could it be the 4ghz cpu? Maybe runs hotter,especially when turbo kicks in? Could it be the 295x compared to earlier cooler running graphics? Well in any case it's bothersome.
     
  2. 5iMacs macrumors regular

    Joined:
    Oct 25, 2014
    #2
    My guess would be the GPU, forum members have already posted about the 100 degree temps that the M295X is reaching on graphics benchmarks, whereas it seems like the M290X is topping out at 86 degrees.

    And according to Intel, these CPUs have virtually the same TDP:

    http://ark.intel.com/products/80810/Intel-Core-i5-4690-Processor-6M-Cache-up-to-3_90-GHz
    http://ark.intel.com/products/80807/Intel-Core-i7-4790K-Processor-8M-Cache-up-to-4_40-GHz

    Anecdotally (take with multiple grains of salt) my experience with i5/M290X has been that it's impossible to heat up the machine with pure CPU load (long Handbrake jobs) but the GPU load kicks in the fans pretty reliably. I have to say that to me they are the most pleasant fans, just the sound of air moving, really, like the rMBP when it's cranking.
     
  3. leenak macrumors 68020

    Joined:
    Mar 10, 2011
    #3
    I have the same config as you and it seems to be fairly quiet. Of course part of my problem is when my husband is home, I'm sitting near him and his monster of a laptop which has loud fans so...

    But when he isn't around, I haven't noticed the sound of the fans.
     
  4. xgman thread starter macrumors 601

    xgman

    Joined:
    Aug 6, 2007
    #4
    I'm wondering if the new CPU heats up at 4ghz+. The load seems to be when heavy cpu computing is going on that spins the fan, like indexing and transferring large amounts of small files and multitasking without any graphics work per se.. I'm not sure the 295x would heat up just because it is driving a "retina" setting on just the GUI of apps etc. I've been used to dead quite for so long during audio music recording sessions that I am now distracted by the fan kicking in so often.
     
  5. 5iMacs macrumors regular

    Joined:
    Oct 25, 2014
    #5
    Well that does sound like pretty definitive evidence. I guess we can't rule out the possibility that Intel is spec'ing the TDP tighter on the i7 than on the i5.

    I'm absolutely sure that the max draw on a long Handbrake job, constant 100% CPU, is 59W (measured with Intel Power Gadget), so the 84W TDP rating from Intel's data sheet is pretty generous.

    http://ark.intel.com/products/80810/Intel-Core-i5-4690-Processor-6M-Cache-up-to-3_90-GHzh
     
  6. xgman thread starter macrumors 601

    xgman

    Joined:
    Aug 6, 2007
    #6
    Today it seems quieted down. I think maybe being a new setup spotlight and Time Mach etc may have been running a lot. We'll see when I get it under loads again.
     
  7. misho73 macrumors member

    Joined:
    Sep 26, 2014
    #7
    I recieved my i7 retina imac today. I noticed the same thing when i tried it with lightroom (exporting pictures) i even created a thread minutes ago before i read this one. I never had this isse with the late 2013 3.5 i7.
    so annoying.
     
  8. macmee Suspended

    macmee

    Joined:
    Dec 13, 2008
    Location:
    Canada
    #8
    Is anyone documenting heat over 100C? If it's just the fan activity you're worried about it's probably nothing.
     
  9. DerekS macrumors 6502

    Joined:
    Jun 25, 2007
    #9
    Calm down. Yes there will be more fan use. You're generating a lot more heat because the CPU and GPU are doing a lot more work than the 2012.

    This does not indicate a fault.
     
  10. FredT2 macrumors 6502

    Joined:
    Mar 18, 2009
    #10
    It seems that that's just the way it is with this model. Faster processor means more heat means faster fans to cool things down. I measured highest fan speed under heavy load of 2700 RPM. That compares with a 2.6 i7 at 5500 RPM doing the same task. Interestingly, the noise generated by each is about the same. They also both get up to about 100 C.
     
  11. dandrewk macrumors 6502

    Joined:
    Apr 20, 2010
    Location:
    San Rafael, California
    #11
    It's perfectly normal, and to be expected because you are driving 4 times the pixels as before.

    That said, the fan seems to speed up at a slightly lower CPU temperature than before. With my older iMac, the fan started spinning faster when the CPU reached 165 deg. F. Now it comes on around 155.

    No biggie. The iMac is still WAY quieter than any Windows PC I've seen or used.
     

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