2014 iMac momentarily stalling. Happened suddenly.

[Mark200789]

Yes, I am still using a nine year old computer as my graphic workstation. It was fine until just two weeks ago. It's an i7 4ghz with 32GB of mem and a Radeon R9 M295X 4GB. I had been using Catalina forever, but mistakenly upgraded to Big Sur last July to make a 3d printing app work better. Things slowed down a bit, but not by much. Frankly, this is still a great machine. But now, in the last two weeks, the computer is stalling randomly in every way. I'll be working and the mouse suddenly lags. The interface will freeze up. And even audio recording lags and then speeds up. This is the worst symptom because it's not just hampering my work but ruining it. It's like the CPU is suddenly too taxed or something, which it shouldn't be. Nothing new is loaded or open. Nothing crazy is taking up cycles in activity monitor. I've reset the computer twice. Any ideas what could be causing this? There in no 27" iMac machine out or on the horizon. The mac studio is a year old. I don't want to upgrade. Please help. Thanks!

 

[ignatius345]

You don't mention the internal storage. Is it an SSD or a Fusion Drive? Either way, I'd check on its health. DriveDx should give you a good bit of info -- you can grab it and run in trial mode to find out what's up. The machine is old enough that your boot drive could easily be failing. I had a 2014 iMac 5K until maybe 18 months ago. In my case, it was equipped with a Fusion Drive and the SSD part of that was reaching the end of its lifetime read/write cycles. I was seeing things a lot like what you describe.

 

[Mark200789]

You don't mention the internal storage...

Thanks for the tip. My drive is SSD only. No Fussion. 256gb with 50gb free. I downloaded Drive DX and it's telling me SMART is reporting 0 issues, the overall health is 100% and the Lifetime Left indicator is 80%. Other health indicators are all good. So, I don't think it's that.

 

[appltech]

If Disk Utility shows Ok to Storage device (Disk Utility > View > Show All Devices > Select the top one > First Aid) and it's not the Fusion Drive.
You may:
-- downgrade to Mojave
-- split Fusion Drive (if is) into the two separate drives (SSD part for macOS using CoreStorage appropriate commands, but to do so you'll need to backup the data and boot into the Internet Recovery Mode
-- upgrade to a new Storage drive (SSD)

Maybe, disabling FileVault + iCloud syncs and TM Backups + Spotlight (add to exclusion all your locations like Mac drive, external drives, etc) + background apps will temporary fix the issue

 

[ignatius345]

Another troubleshooting step you might try is creating a brand new user account and seeing if the issue persists.

- Open Users & Groups and create a new user account
- Reboot
- Log in to that new user account only, not your usual one. It'll harass you to tie it to your Apple ID, but easier if you skip that (so it doesn't waste time syncing, etc).

Now under that new account try doing whatever it was that was causing you grief. If it goes smoothly, you might have an issue related to your own user account. If it's still stalling out, you know it's something system-wide or something in hardware.