Late 2014 27” iMac Sleep/Power Off Issue

[theadder]

I have a Late 2014 27” Retina iMac (iMac15,1) with i5-4690 CPU, M295X GPU, and 32GB Crucial RAM.

I have an issue where the iMac will go into a sleep state during use; rarely, the system powers off entirely and I have to turn it on again.

The sleep/power off issue occurs during certain types of video playback (especially videos from the Twitter website) and while running games (primarily Civ 6). Obviously, this is fairly frustrating.

The incidence of the problem varies a lot. In some cases, entire days can pass without the issue (even when I’m using the machine for the tasks that trigger the problem. The issue manifests with higher CPU/GPU temperatures, but high temperatures can exist without the issue occurring. I’ve tried resetting the SMC, but that didn’t seem to have much effect.

Ultimately, I plan to replace the machine with an Apple Silicon Mac. Any suggestions in the meantime? Is anyone familiar with this as an issue?

 

[hobowankenobi]

There have been several sleep-related issues over the years. Some seem to be linked to hardware (specific GPUs, etc), while others seem like a OS issue. The fact that it is happening during video playback makes me think it may fall in the GPU category. But, it might make sense to consider a different OS version, depending on what you are running.

If you have an external drive handy, you could try a bootable OS of a different version to test with, without having to change or otherwise interrupt your current OS/workflow.

Have you already tested while Safe Booted to rule out third party software and extensions? Tested from a clean/new/test user account?

 

[satcomer]

Also it’s well known that computer chip chip compound for thermal protection can dry out on such old Macs! So open it up and change the thermal components on your Mac’s processor! This will greatly help on thermals!

 

[theadder]

Thanks for your suggestions.

I seem to have been able to resolve the issue with some really concerted use of compressed air — I really wanted to avoid opening it if at all possible.