iMac A hotter than iMac B in gaming

Discussion in 'iMac' started by MythicFrost, Jan 27, 2016.

  1. MythicFrost macrumors 68040

    MythicFrost

    Joined:
    Mar 11, 2009
    Location:
    Australia
    #1
    There're two different iMacs in my household, both are the exact same system (27", i5 3.4GHz, GTX 775M 2GB, 16GB RAM) but iMac A's GPU runs hotter than iMac B by 8-10 degrees. The real problem is that the fan on A sounds like a hover jet and B's doesn't.

    Both running recent installs of Windows 10 with identical settings, running the same game (Dawn of Discovery: Venice) at the same time with the exact same settings. iMac B has Windows installed on a hard drive whilst iMac A has it installed on an SSD (USB 3 w/ UASP)

    See attached images for max GPU temperature.

    Any thoughts on what this can be?
     

    Attached Files:

  2. bogg macrumors 6502

    bogg

    Joined:
    Apr 12, 2005
    Location:
    Sweden
    #2
    Have you tried resetting the SMC on both computers to see if they even out?
     
  3. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #3
    They seem to be off a couple degrees, or am I missing something?

    I don't think that's a wide enough variance to worry about.
     
  4. bogg macrumors 6502

    bogg

    Joined:
    Apr 12, 2005
    Location:
    Sweden
    #4
    59 vs 70 as current and 82 vs 89 at peak seems more than a couple of degrees. But I concur, if the difference stays after SMC reset OP should chalk it down to manufacturing differences. The low temp also seems to be of the same variance so maybe the sensor is of, or the heat paste isn't equally applies between the two.

    Also the environment could make a difference, are both placed in the same room with the same ambient temps, and no sun shining directly on any of the two?
     
  5. MythicFrost thread starter macrumors 68040

    MythicFrost

    Joined:
    Mar 11, 2009
    Location:
    Australia
    #5
    Thanks for the replies guys!

    Not yet. I'll try that on mine, and see if I get a better result next time.

    I'm looking mainly at the max temperature of the GPU which differs by 7 degrees. (And it's done this consistently.)
    I see, I see. Interesting. Yep I'll try the SMC reset, and see how that goes. Both are in separate rooms which are air conditioned, and both computers are out of the sun. Ambient temperature should be very similar, if not the same.

    The best test would be to probably move them to the same room, but I'm not sure I'm that invested in finding out that I'd pull iMac B out of its jungle of cables and external drives :D

    >>>

    Ignore the current temperatures though, as the screenshots were taken at different times after the game had closed.
     
  6. maflynn Moderator

    maflynn

    Staff Member

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    Location:
    Boston
    #6
    7 degrees isn't a lot, as Bogg stated, just chalk it up to manufacturing differences.
     
  7. Samuelsan2001 macrumors 603

    Joined:
    Oct 24, 2013
    #7
    Agree with Maflynn, every computer is different hell very CPU and GPU runs slightly differently without taking all the parts into consideration.
     
  8. T'hain Esh Kelch macrumors 601

    T'hain Esh Kelch

    Joined:
    Aug 5, 2001
    Location:
    Denmark
    #8
    Temperaturegate.

    No, nothing interesting to see here I agree. Application of thermal paste underneath the chips can vary hugely between machines, and may be the cause of this.
     
  9. Strider64 macrumors regular

    Strider64

    Joined:
    Dec 1, 2015
    Location:
    Suburb of Detroit
    #9
    After having built many PCs before buying my first iMac that temperatures vary because of various factors, such as size of the CPU, amount of TIM applied to between the heatsink and cpu, graphics card, etc... Temperature readings can even vary on the same computer (the bios reading is usually the most accurate). The only time I got concern is when a computer went above 150F for a very long period of time, but usually safeguards shutdown the computer when it starts to over heat (not always depends on the motherboard manufacturer).
     
  10. MythicFrost thread starter macrumors 68040

    MythicFrost

    Joined:
    Mar 11, 2009
    Location:
    Australia
    #10
    Thanks for the replies guys. Interesting... I don't care about the temperatures per say, but A's fan revs to max which is noticeably louder than B's, tis' a bummer but oh well.
     

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