What's a safe GPU diode temperature?

_Skyfire_

macrumors newbie
Original poster
Aug 16, 2017
22
7
Recently bought a used 27" 2017 iMac with the Radeon 580 and took a look at the temps & fan speeds. Mostly because I remember an earlier thread warning how high temperature is what kills computers.

So being that my most intensive use is bootcamp gaming, I downloaded Macs Fan Control and took a look. Running AC Odyssey on very high settings at 1440p the highest temp was GPU diode, reaching into the high 90's C (>200 F) before the iMac fans started kicking in.

I subsequently used MFCs custom range for ambient temp to enable the fans kicking in way earlier. With moderate fan speeds the GPU diode kept at 89 C (192 F) whereas with higher RPMs I managed a sustained 87 C (189 F).

For a layperson like me, even high 80 C seems like a very hot temperature for a component to operate without eventually breaking. But I'm sure there's a more knowledgeable person who can answer that.
 
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SecuritySteve

macrumors 6502a
Jul 6, 2017
744
858
California
I've noticed the fans tend to not be audible, even when they are indeed on, in modern iMacs and especially iMac Pros. Your fan is likely on at 150 F, you just can't hear it.
 

Ledgem

macrumors 68000
Jan 18, 2008
1,755
506
Hawaii, USA
Heat does kill electronics, but I recall reading before that what really kills electronics is the fluctuations in temperatures. So, for example, powering down, being off for a time, and then powering up - that period where the voltage goes up and temperatures rise rapidly represents more stress on computer components than simply running at a higher temperature. It was an argument for keeping a device on, instead of turning it off and on multiple times a day. (Granted, running all the time isn't power-friendly - do what you need to do, knowing that nothing lasts forever...)

You can look up technical information on the operating temperature ranges, and as long as the device is within those ranges, it should be fine.
 

_Skyfire_

macrumors newbie
Original poster
Aug 16, 2017
22
7
I've noticed the fans tend to not be audible, even when they are indeed on, in modern iMacs and especially iMac Pros. Your fan is likely on at 150 F, you just can't hear it.
Of course the fan is on. By "fan kicking in", I meant it rising from the base speed of 1200 rpm and becoming audible.

Heat does kill electronics, but I recall reading before that what really kills electronics is the fluctuations in temperatures. So, for example, powering down, being off for a time, and then powering up - that period where the voltage goes up and temperatures rise rapidly represents more stress on computer components than simply running at a higher temperature. It was an argument for keeping a device on, instead of turning it off and on multiple times a day. (Granted, running all the time isn't power-friendly - do what you need to do, knowing that nothing lasts forever...)

You can look up technical information on the operating temperature ranges, and as long as the device is within those ranges, it should be fine.
That's valuable information, thank you.

Would you happen to know where I could find technical info on the operating temp range of the GPU diode or some of the other critical components? I did a fair bit of searching but alas, didn't stumble on it
 

Ledgem

macrumors 68000
Jan 18, 2008
1,755
506
Hawaii, USA
Would you happen to know where I could find technical info on the operating temp range of the GPU diode or some of the other critical components? I did a fair bit of searching but alas, didn't stumble on it
The companies used to publish it as part of the specifications, but with GPUs I suppose it's a bit harder because they're packaged differently through different companies. I did a bit of searching, as well, and couldn't find anything specific to this card. This website (which I'd imagine you ran across as it was one of the top results on Google) states that modern GPUs have maximum operating temperatures around 95˚C (although I'm not sure where they're getting that number from), but they also admit that there are cards that go beyond that. The temperatures they give for Nvidia cards are apparently from the company, but the AMD numbers are just averages from other people's computers, which isn't useful for us iMac users. I suppose the next best thing to look for would be if there's a database collection of temperatures from other people's computers, to see if your numbers are way off from others or if you're in line with others. Unfortunately I don't know of any such database; I found one for CPU temperatures but it only seems to cover computers up through 2016 models, and I don't see an area for GPU temperatures. I wonder if it might be worth contacting Bjango (makers of iStat Menus) to see if they happen to collect anonymous data... otherwise, just trying to get word of mouth about other people's temperatures would have to do.

For what it's worth, I don't game, but my GPU is utilized for photo editing. I'm using a late 2015 iMac with an R9 M395X, and looking over my temperature ranges from the GPU die from the past week, my high was 73˚C, with a low of 49˚C. Different graphics card, though, doing different applications, so it may not mean much.