GPU Reset (.gpurestart) after brand new logic board replacement.

Make sure to disconnect all external devices from the computer in case one of them is causing a problem.

Do these GPU Resets happen if you perform a clean install of macOS by first erasing the internal SSD followed by reinstalling macOS? Make sure to test a clean install thoroughly before you install any third party apps and before restoring from a backup since you don't won't to bring the problem back again during your testing.

If you still get the GPU Restarts after a clean install under these conditions, then you have confirmed a hardware failure.

You can also try running the Apple Diagnostics to see if any hardware issues are detected. Unfortunately the only useful diagnostic is one where an error code is produced (or the diagnostic freezes during testing).

You have a 90 day part/repair warranty with the previous repair. Make sure you resolve this issue within that time, or that Apple is at least working on the problem for you (I would want some type of written confirmation any repairs will be covered if you are nearing the end of this 90 day warranty period). Just having a case open with Apple isn't usually enough to ensure coverage.

tdawg1987 wrote:

2) I guess my concern is, how many clean installs do I need to do? If I can ever restore from a backup what’s the point of having one? It just takes so much time to have to reinstall everything… lol.

The point of not installing third party apps & restoring from backups is just for testing the computer to confirm a hardware problem. As soon as you add a third party app or restore from a backup, you potentially re-introduce the problem again making it impossible to determine if hardware is the source of the problem, or whether it is a software issue, or configuration issue. Testing in this state is only meant to be temporary. It is also one of the first things Apple will usually require of a user before considering repairing the hardware.

Of course you can try installing & testing a clean OS from an external drive. Most times this will achieve the same results as performing & testing a clean install on an internal boot drive....except if the internal SSD is at fault, or with a 2018+ Mac....the security enclave chip may need to be reset which is only done with a firmware "Restore". It really depends on the issue....with a GPU Restart issue, testing a clean install from an external drive is probably enough.

3) Apple said I need to replace the logic board again (and they are covering it).

That is good since I suspected the Logic Board was at fault. When you mentioned this GPU Restart issue is new only after the replacement Logic Board, it just reinforced my suspicions.

Keep in mind I know nothing about your computer and it setup or history except for what you provide here....even then I must be careful not to assume too much as it has burned me before when assisting others on these forums.

Such a frustrating process. I just want to know why these things continue to happen overnight when the computer is asleep.

Powering on and waking from sleep are the two most stressful moments for a device so it is also the time a failure is most likely to appear.

FYI, I have seen a lot of Logic Board failures with the 2018+ Macs (especially the 2019 models of all types and even the 2020 iMac) while supporting thousands of Macs for our organization. I have started becoming concerned about whether we should even have these Intel models repaired. It does not surprise me that a replacement Logic Board is already causing you problems. Just make sure to have Apple resolve any issues within 90 days of your repairs so they will be covered.

Good luck with the next Logic Board.

Sorry to hear the bad luck. It is very unusual to get so many bad boards even if it is a 2019 model. I just wonder if the built-in Display Assembly may have a problem which is causing these GPU Kernel Panics especially since you did not restore from TM and did not have any external devices connected.

You may want to suggest that to the tech.

Edit: I forgot this is an iMac. I did notice on our 2019 iMacs the heatsink screws seemed really loose as I could easily snug them up without any effort, I've never seen a heatsink screw that loose for any other system. Not sure if this is how it should be or if the screws are actually a bit too loose.