Possible 5K iMac Graphics Card Overheating Issue

The iMac’s fan is quite silent; at its default speed of 1200 rpm, I don’t hear it. The only times it revs up is when I’m using Skype for videoconferencing, or when I rip a video with Handbrake. I have a late 2014 5K iMac with the AMD Radeon R9 M295X graphics card.

But in recent days, I’d noticed that my iMac’s fan was running more often than usual. Since I already use iStat Menus, I set up the app to display sensors in a menu. The menu displays temperatures and voltages for more than a dozen locations in the Mac.

At the time, I noticed that the GPU Die was showing a temperature of more than 90 C, even when the Mac wasn’t doing anything. You can see the spikes early in the Last 7 Days graph, when it was over 100 C when viewing a video. It reached as much as 105 C, which is not necessarily a problem, but the fact that it didn’t go below about 90 C was suspicious. (Note that the peaks in the last hour occurred when I was running a GPU benchmark app, which pushed the graphics card to the limit.)

I couldn’t find any conclusive information about this on the internet, so I contraction Apple. The technician checked and said that it certainly wasn’t a normal temperature. He was prepared to set up a repair, but first had me reset the SMC then reset the NVRAM on the iMac.

To my surprise, this resolved the issue. The resting GPU Die temperature dropped to the 50s-60s C range, and the fan no longer runs fast when I’m not taxing the computer.

So if you encounter this issue, try the above steps: reset the SMC, then the NVRAM. Please post a comment if this does resolve the problem, or if it doesn’t.

20 thoughts on “Possible 5K iMac Graphics Card Overheating Issue

  1. Mine has just started experiencing an issue, screen will go black, temps are 106 plus tried reset to no avail, hope a new gnu is not needed

  2. Mine has just started experiencing an issue, screen will go black, temps are 106 plus tried reset to no avail, hope a new gnu is not needed

  3. Mine is the exact same year, model and spec, if I worked the computer hard with video it would eventually get to 110 degrees on the GPU diode and decide to go to sleep. Looked like a self-safety thing.

    After many hours of phone support to establish it wasn’t iTunes (this is where I was playing the 4K videos) they eventually agreed it was hardware. Seems to be a well known problem with the iMac and it’s ability to disperse heat easily.

  4. Mine is the exact same year, model and spec, if I worked the computer hard with video it would eventually get to 110 degrees on the GPU diode and decide to go to sleep. Looked like a self-safety thing.

    After many hours of phone support to establish it wasn’t iTunes (this is where I was playing the 4K videos) they eventually agreed it was hardware. Seems to be a well known problem with the iMac and it’s ability to disperse heat easily.

  5. I’m having the same issue with my 2014 riMac, that’s the reason I found your post. I’m going to try the fix, because this is something that definitely wasn’t normal in the first couple of years of service. I even had a shutdown watching a YouTube clip. Will report back…

    • I can confirm that resetting the SMC and NVRAM didn’t make a differnce. Logging into icloud.com and staying on the main screen (with animated background) for 10 seconds in Safari is enough to make the fans spin up. I’m not sure what to do.

  6. I’m having the same issue with my 2014 riMac, that’s the reason I found your post. I’m going to try the fix, because this is something that definitely wasn’t normal in the first couple of years of service. I even had a shutdown watching a YouTube clip. Will report back…

    • I can confirm that resetting the SMC and NVRAM didn’t make a differnce. Logging into icloud.com and staying on the main screen (with animated background) for 10 seconds in Safari is enough to make the fans spin up. I’m not sure what to do.

  7. I have the same problem. Bitwig does it, VCV Rack does it… all kinds of programs seem to fry the GPU (AMD Radeon R9 M295X). If you have a solution, PLEASE post it. It’s driving me nuts.

  8. I have the same problem. Bitwig does it, VCV Rack does it… all kinds of programs seem to fry the GPU (AMD Radeon R9 M295X). If you have a solution, PLEASE post it. It’s driving me nuts.

  9. The same problem here. In my case background render FCPX. GPU die goes to 106 and then the screen blacks out. Water cooling mod anyone? 🙂

  10. The same problem here. In my case background render FCPX. GPU die goes to 106 and then the screen blacks out. Water cooling mod anyone? 🙂

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