iMac 27 inch scary temps

[JHorace]

So I recently bought a 27 inch imac with the i7 cpu and 680mx gpu. Yesterday I purchased the game DMC and was running it on the highest possible settings in Windows 7 when I was suddenly sent back to the desktop and my imac restarted. There wasn't any error message, it was as if I had restarted it myself.

I was worried the problem may have been caused by overheating. When things get more graphically intense, the fan turns on, but it isn't particularly loud. Anyway, I installed a program called Real Temp GT to see how hot things were getting, and booted up DMC again. After running it for an hour I exited and checked Real Temp and it read that the maximum temp reached during gaming was a rather terrifying 97 degrees celsius!

During this time there seemed to be barely any heat coming from anywhere on the machine; the back seemed totally cool.

I was just wondering whether I should be terribly worried. Its always possible that Real Temp doesn't play nice with iMac hardware, so I also wondered if anyone could suggest any other monitoring software.

Thanks

 

[WilliamG]

This doesn't surprise me. For some reason, when playing Devil May Cry the fans don't speed up very much. I'm not sure why...

Download Lubbos (google it), and set your fan speed somewhere between 2000rpm and 2500rpm, and you'll be good to go.

 

[AndiS.]

This doesn't surprise me. For some reason, when playing Devil May Cry the fans don't speed up very much. I'm not sure why...

Download Lubbos (google it), and set your fan speed somewhere between 2000rpm and 2500rpm, and you'll be good to go.

Same seems to be true for 3DMark 11, the fans don't speed up at all and realtemp measures over 90 degrees Celsius maximum on all 4 cores. I find this very strange, shouldn't the fans counteract the heat in general? Why is this dependent on the program that is running? When I play games like Assassin's Creed 3 for 2+ hours the fan becomes very noticeable, never checked the temps before though.

I haven't had any negative effects from overheating so far, and the unit I'm using right now will be replaced next week, but I'm a bit concerned about what will happen in the summer, when ambient temps are way higher.

 

[JHorace]

Thanks for the advice on Lubbos.

I guess it can't get data from the temp sensors on the cpu so it thinks the temperature is always 90 degrees, which means the fans never slow down. This is fine, I just turn it off when I'm not gaming. I wonder though whether there might be a similar problem with Real Temp and the shutdown was for unrelated reasons. I'll test a few other games and report back.

Just wondering though; does anyone else feel the heat when their mac gets hot? Mine seems totally cool even at supposedly high cpu temperatures.

 

[WilliamG]

Thanks for the advice on Lubbos.

I guess it can't get data from the temp sensors on the cpu so it thinks the temperature is always 90 degrees, which means the fans never slow down. This is fine, I just turn it off when I'm not gaming. I wonder though whether there might be a similar problem with Real Temp and the shutdown was for unrelated reasons. I'll test a few other games and report back.

Just wondering though; does anyone else feel the heat when their mac gets hot? Mine seems totally cool even at supposedly high cpu temperatures.

Most of the heat is further down the system, around where the RAM goes in. So the RAM is the last component to cool off before the air exits the system. It is true that the iMac 2012 runs cooler than any other iMac I've used.

And yes, Lubbos needs an update to support these new systems. I just set my fan to ~2200rpm when I'm gaming, and then set it back down when I'm done. If I forget to set it back to default, I use iStat Menus in OS X to reset the fan, since it doesn't reset automatically on reboot unless you turn the iMac off, first.