11 Replies Latest reply: Mar 29, 2013 6:12 AM by WZZZ
Sweetmacdo Level 1 (0 points)

Hi comunity!

Now (finally) i got my New imac 27" i5 with 1TB Fusion Drive. I used the migation app. with Time Machine Back up of my early imac 20" 2006 to fill it with live.

My Question: How hot should the Gaphic Card (GTX 680 2GB) run during playing f.exampl. WoW?

Istatpro tells me 84°C (183,2°F) and the Fan howls up for a few Seconds. Than it falls back to about 70°C (158°F). This repeat´s every 3-5 min during gaming.

Is that a normal behave of my new iMac? Or is the Grafic Card broken?

Thanks in advance for any answers.



OS X Mountain Lion (10.8.3)
  • mende1 Level 10 (92,186 points)

    Welcome to the Apple Support Communities


    That's a sign that your iMac is working properly. When you are playing a game, the graphic card can increase a lot the temperature, but the sensor detects a high temperature and fans increase their speed, so the temperature decreases. As I told you, your iMac is working properly and there's nothing to worry

  • Level 8 (41,760 points)

    Hi Stefan,


    Congratulations on the new iMac, great machine.


    No, the graphic module is probably not broken...you are more than likely pushing it pretty hard with gaming.  Some gaming is very, very graphic intensive and drives the GPU really hard.  How does the iMac behave under less demanding usage?  When you internet surf, etc, do you see a temp rise?  Use the iMac for various tasks and keep track of the behavior of the GPU so you can see if it is just heavy gaming that is a problem or if it is for general use also.



  • Level 8 (41,760 points)

    Hey mende, you are really typing a lot faster than I am today

  • mende1 Level 10 (92,186 points)

    That's because in Maryland it's early morning at this moment (am I wrong?). And I drank coffee, too :-)

  • Level 8 (41,760 points)

    That would be the problem, I have only had one cup of coffee so far...will go get another so we can race

  • Sweetmacdo Level 1 (0 points)

    Hi macusers!


    Thanks for that vivid feedback!

    My concerns are eliminated,thanks a lot, folks!


    @ Ralph: No, this behavior is only when i am playing 3D games, in gereral use this machine is quite silent and cool! (in many ways;-))




  • mende1 Level 10 (92,186 points)

    You are welcome

  • Level 8 (41,760 points)

    You are welcome, Stefan.  And that would indicate there is nothing wrong with the iMac, just a very heavy load when running 3-D games, which others have asked about in the past.  That iMac is a potent machine, but being so compact things that load the system heavily produce a lot of heat the fans have to dissipate...they are just doing their thing keeping the insides cool.


    Enjoy the iMac.



  • WZZZ Level 6 (12,855 points)

    Over time, that kind of heat will possibly wreck the graphics chip, and other hardware components. I would get smcFan Control, create a pre-set where the fan will ramp up to around 2K and use that while runnng games. I would create other pre-sets as well. I don't think that computer is designed for a very long life.

    See my posts in these two threads for more infomation. (Note. My settiings reflect the default fan speeds of my late 2009 iMac; yours will be different, and you only have one fan.)






    That new iMac is very cramped inside. You can help it dissipate the case heat by running a small fan at the back. The aluminum back acts as a huge heatsink, so moving the heat off that with cooler air will help.

  • Level 8 (41,760 points)

    WZZZ, you would be better off aiming that fan to blow sideways across the back, or even better upwards.  Forced convection heat transfer is greater when the flowing fluid (air in this case) is across the surface rather than directly at the surface.


    When I need to do a lot of heavy calculations with my MacBook Pro, I place it on the granite counter top in the kitchen...huge heat sink (not too close to the water sink ) to dissipate a lot of heat.

  • WZZZ Level 6 (12,855 points)

    The photo is a bit deceptive; the fan is aimed upwards so it doesn't block air escaping from the the long exhaust slot at the top. What I  also like about aiming it straight on and not sideways is that the main intake grille is right behind the stand and the stand shields that grille from a direct hit by the fan. Sideways I'm afraid it would aim more dust right into that grille. (I brush out and vacuum that grille periodically.)


    The proof is in the touching: I'm running the fan right now and the back is very cool to the touch. It was starting to get kind of warm before I turned it on.


    During the summer when it gets really hellish here, no amount of blowing hot air around will have any effect. I keep a close eye on the temps and just sleep the computer more often then.


    Message was edited by: WZZZ