brand new 5k imac GPU heating to ridiculously hot levels under mild use

This may be one of these cases where Apples design has taken prescience over function. It wouldn't be the first time the laws of thermodynamics has hit Apple in the back of the head. I would like to see what Apple's official response on this would be, and I think many machines will be getting fixed within only a few years. I remember the G4 cube debacle of over heating, or the G5 iMac overheat problem, or the G4 laptop over heat problem, Apple has had an overheating issue on many of its systems over the past decade.

whats normal? , well according to intels own spec sheet the i7 processor shouldn't exceed 90c and if gets to 105c it will wind down clock speed. Any chip hitting near 100C is too hot in my 30 year experience with electronics , but hey maybe apple made some super special chips that can run sustained at 100c for days on end. I doubt it though.

IMHO it needs a small liquid cooling system to keep chips at 50c or less. Fans just create more noise. The quad G5 had a liquid cooling system! I AM SURE they can manage one in the iMac. Just make the back thicker who cares if a desktop is thin or thick ??!?!?

UPDATE:

After some experimentation, I have found that setting the fan speed at ~1800rpm that it keeps the GPU Die between 74-76C which should be well within the acceptable range. To me it looks like the system needs more that one sensor to trigger higher fan speeds. The other sensors stay in the 40-50C range so the fan stays at 1200rpm. With iStat Menus it is very simple to add a new fan speed rule and use that whenever I watch full screen videos.

Hope this helps someone.

Top of the line iMac 5K maxed out all the way.

223 degrees F, I can boil water on the GPU DIE , hopefully the GPU won't burn up and DIE.

GPU proximity sensor 133 degrees F.

Fan speed 2300 rpms

Seems to me that in order to make the iMac quieter they limited the fan speeds.

Apple should have put two fans in one for the CPU and one for the GPU.

So far it works great just scares me about the long term effects of heat on the chip and board.

Apple needs to look at a software fix to increase the fan speeds before the temps rise.

even the max default fan speed 2300 rpm produces the above results.

I have just got off the phone with apple about this, and their statement is, this is fine for this machine, there are no issues at operating high loads for sustained times. They even said the istat 3rd party tool that people are using to monitor temps is not an accurate measure of true core chip temps. They admit these machines will run hotter than most macs , but its nothing to be concerned about.

so in summary, work them hard, and enjoy the machine and stop worrying about fan speeds and temps!

I wouldn't trust what Apple says about this. Long term, heat kills. The tech you spoke to doesn't care in the least if the GPU in anyone's computer dies in a few years. I also wouldn't necessarily take as gospel that iStat Menus isn't accurately reporting the temps.

I don't know if Marcel Bresink (Hardware Monitor) has updated his program for the newest Macs, but you might want to get it on a trial basis to see if it concurs with iStat. His stuff is the gold standard.

Too late to create edited reply:

I wouldn't trust what Apple says about this. Long term, heat kills. The tech you spoke to doesn't care in the least if the GPU in anyone's computer dies in a few years. All he cares about is putting a smiley face on Apple products. I also wouldn't necessarily take as gospel that iStat Menus isn't accurately reporting the temps. What is his information on this based on? How does he know?

I don't know if Marcel Bresink (Hardware Monitor) has updated his program for the newest Macs, but you might want to get it on a trial basis to see if it concurs with iStat. His stuff is the gold standard. (If you have Gatekeeper set to restrict programs that are not code-signed, you will need to create an exception. Hardware Monitor is perfectly safe).

You will all know in a few years--possibly after everyone's AppleCare expires-- if the GPU chip in this model is known to be vulnerable to these high temps. Logic board replacements aren't cheap.

The Apple tech may or may not be wrong, however, I would at least take what he says with a huge grain of salt. For anyone who may be affected by this, I would call Apple and get it on record that you were concerned about the heat at the GPU die. That way, even if your 1 yr warranty or 3 year AppleCare expires, you may be able to hold their feet to the fire.

Can anyone post back with the exact name of the GPU chip. Maybe there are reports already on this being vulnerable to excessive heat. You might also want to contact the chip manufacturer (NVIDIA, or whoever that may be), to ask them what the heat tolerance for the chip is, and if they have any reports of problems with this chip.

Not much you can do at this point, the facts are, AMD have not given apple normal operating ranges of temps, beyond 105C is its upper thermal limit. Intel have not produced or published anything on the i7 Processors upper limit, Apple have no data of these failing on mass or indeed at all due to heat, there is no issues (as yet) thus they wouldn't even take my excuse as this is a design flaw and I would like a refund.

So I suggest we all lodge a help desk call, loge a complaint and a case number and let things progress from there. Beyond that, it could be nothing, or it could a xbox 360 red ring of death issue that presents itself in a year or two ?

According to the Hardware Monitor link: http://www.bresink.com/osx/216202/Docs-en/whatis.html

This utility can't be used on the new Mac OSes.

The application is only designed for use with Apple-branded computers released between August 1, 2002 and October 31, 2012. It cannot be used with other model series.

I have an iMac 5K M295.

Playing Watch Dogs pushes the temps to 73 for CPU 105 for GPU in Windows. Room temp is around 20 degrees Celsius.

I think a lot of video cards have 100 degrees, like my ATi HD 4850 single slot, that's constantly over 100 degrees when playing games (still works), and the nvidia GTX 570 no custom cooling.

Of couse I would like custom cooling, like my 2nd ATi HD 4850 runs at only 70 degrees max hahahaha.

I noticed iStat Menus just issued a release with "improved" support for 5K iMacs. Upon a VERY quick test it seems it is not reporting as high on GPU Die temp doing stuff that used to smoke it. There have also been several flash updates since then so maybe they have tuned their use of graphics hardware acceleration. This was the culprit with mine, of course if you turn that off, then all four processors got much hotter.

Good Luck.

Love the iMac, only a periodic Sleep/Wake restart is last bug I see.

Using iStat Menus, the 5k iMac still registers very high temperatures near the GPU Die. Based on that, I've started using a more aggressive approach to the fan.

With normal web browsing, the die hits 150 degrees F; doing graphics processing, the heat hits 190 degrees F. Overheating the GPU can cause damage, so I make sure the fans kick in when there's the slightest chance of a problem.

In other words, it's still an issue - but can be managed with prudent fan usage.

My GPU Diode was hitting 108C and my iMac would go to sleep to try to save itself. I installed TG Pro to increase the fan speed manually, but had to keep it on full blast to prevent sleeping and it was still ~100C at all times. TG Pro was reporting my max fan speed as ~2400 RPM (don't recall exact number, but was below 3000). I reset my SMC and now my max fan speed is reported as 3170 RPM. With the higher max speed, the default automatic fan control is now keeping everything below 95C. So if you find yourself requiring manual fan control, check your max speed and reset SMC if it's not 3170 RPM. My SMC version is 2.23f11

Grant Burton wrote:

Not much you can do at this point, the facts are, AMD have not given apple normal operating ranges of temps, beyond 105C is its upper thermal limit. Intel have not produced or published anything on the i7 Processors upper limit, Apple have no data of these failing on mass or indeed at all due to heat, there is no issues (as yet) thus they wouldn't even take my excuse as this is a design flaw and I would like a refund.

So I suggest we all lodge a help desk call, loge a complaint and a case number and let things progress from there. Beyond that, it could be nothing, or it could a xbox 360 red ring of death issue that presents itself in a year or two ?

You bring up a good point: where is the dividing line between normal computing tolerances and a computer with serious problems? Some might say it's just a matter of time, especially if you're dealing with high temperatures.

I think it makes sense to be proactive. No guarantees, of course, but it's less likely you'll experience a fried graphics board or HD if the temperatures are kept as low as possible. Some users don't want to use their fans too much, but to preserve my investment, I'm making sure my machine is as cool as a cucumber.