iMac 27 inch or iMac 5K 27inch (late 2014)

Discussion in 'iMac' started by ChrisCarmona95, Mar 26, 2015.

  1. ChrisCarmona95 macrumors newbie

    Joined:
    Mar 26, 2015
    #1
    I currently have the iMac 5K with 16GB RAM, i7 4.4 ghz with AMD Radeon m295x GPU

    Now one thing I don't like is that when I'm playing games the GPU goes up to 105 Celsius. If I were to switch my current iMac to a
    27inch iMac with 16 GB RAM, i7 3.5 ghz, NVIDIA GeForce GTX 780M 4GB GDDR5 GPU

    will it run just as hot since it's not a Mobile GPU or will it be the same? I mostly play games like Total War and that's about it, besides video editing.
     
  2. yjchua95 macrumors 604

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    GVA, KUL, MEL (current), ZQN
    #2
    It'll run at more or less the same temperature.

    I play BF4 on my 780M iMac, and average temperatures are normally above 95ºC.
     
  3. ChrisCarmona95 thread starter macrumors newbie

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    Mar 26, 2015
    #3
    How long have you had the Mac for? Have you had any issues overtime for running at 95°C frequently because I barely have a week with mine and so far it runs like a champ! I have apple care so it doesn't really bother me as much. I'm just curious about these temperatures
     
  4. yjchua95 macrumors 604

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    #4
    I've had it since launch, and been running like that (but mainly due to video editing and CUDA software) almost daily.

    So far it's still good.

    Meanwhile, my i7/32/512/M295X retina iMac also runs pretty well. I'm not concerned about the temperatures either.
     
  5. Alesc macrumors 6502

    Alesc

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    France
    #5
    On my late 2013 iMac, I've never seen a temp higher than 85-90°C ingame for the GPU (Alien Isolation, Bioshock 2, Max Payne 3).
    And now, before playing, I'm forcing the fan @2000 tpm in order to keep my GPU cool (with that system, it never get warmer than 75-80°C).
     
  6. andy9l, Mar 27, 2015
    Last edited: Mar 27, 2015

    andy9l macrumors 68000

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    England, UK
    #6
    iMac 27 inch or iMac 5K 27inch (late 2014)

    In your existing 5K iMac:

    1. The M295X reaches ~105°C,then thermal throttles (well, dynamically lowers clock speed) with fan at 2300rpm
    2. The 4790K i7 reaches ~100°C and thermal throttles with fan at 2700rpm
    3. The two together will both thermal throttle under load with fan at 2700rpm (all within a few seconds)

    This video best explains it for the CPU specifically.

    In the 2013 iMac you're proposing, this will not happen and it will run cooler. You may see a minor performance hit, though, since even when throttled, the 4790K/M295X perform relatively well.

    The i7/M295X 5K iMac suffers from a cooling system that has proven to be insufficient for the components inside, however, it looks as though Apple purposely chose this route. There is probably no danger, as such, just throttling.

    Edit: to be clear, by 'insufficient' I mean the system *relies* on thermal throttling. You could argue if that is truly insufficient or not, I guess.
     
  7. AppleFan360 macrumors 68020

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    Jan 26, 2008
    #7
    Proven by whom? And don't give me links to Joe Shmo on the internet who doesn't work as an engineer in the computer field.
     
  8. andy9l macrumors 68000

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    Aug 31, 2009
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    England, UK
    #8
    iMac 27 inch or iMac 5K 27inch (late 2014)


    The monitoring software is not 'Joe Shmo'. Install it on your machine and try it for yourself - it's not difficult. I managed it.

    Edited my post for clarity, though.
     
  9. AppleFan360 macrumors 68020

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    Jan 26, 2008
    #9
    I've installed it. I've seen it. Still doesn't mean anything especially since the machine hasn't blown up.
     
  10. andy9l macrumors 68000

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    Aug 31, 2009
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    England, UK
    #10

    Glad we cleared that one up, then.

    Just for anyone else who was wondering, I was not suggesting that the 5K iMac may blow up.
     
  11. Samuelsan2001 macrumors 603

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    Oct 24, 2013
    #11
    They are both using

    Mobile GPU's and they'll both run hot when you max them out as they would do in any computer.
     
  12. zhaoxin macrumors regular

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    Jan 28, 2015
    #12
    GTX 780M is also a mobile GPU. 780M, M for Mobile.
     

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