2011 iMac gray error screen - kernel panics?

[flat6pilot]

So I'm a new Mac owner after a twenty year hiatus from the brand. Feels great to be back. Picked up a Mid 2011 21" iMac i5 2.5GHz off Facebook marketplace for $180 and immediately installed the OWC SSD Upgrade kit without any issue.

I ran it for about five days on the stock 4MB and experienced 1 gray screen saying "your computer restarted because of a problem". I then upgraded to 32MB from OWC and have been getting the same gray error screen about every 24-48 hours. Unsure if the increase in frequency is coincidental or related to the new memory because I've only been running the machine for nine days total. High Sierra 10.13.6.

Not doing any special when the error occurs other than running several browsers with multiple tabs (Safari, Chrome, Firefox, Opera).

This will obviously get annoying really quick. What's the fix or common causes?

 

[mdgm]

Have you run Apple Diagnostics? One possibility is faulty or not properly seated RAM.

 

[flat6pilot]

Have you run Apple Diagnostics? One possibility is faulty or not properly seated RAM.

Nope not sure how to run Apple diagnostics, still learning my way around the OS.

 

[mdgm]

When you boot hold down the D key.

See https://support.apple.com/en-au/HT202731

 

[flat6pilot]

When you boot hold down the D key.

See https://support.apple.com/en-au/HT202731

Will try and report back thanks!

 

[mdgm]

If holding down D doesn’t work you can try Alt+D which will use the Internet Recovery method to launch diagnostics.

 

[nambuccaheadsau]

Using D key will not work as this only became available on models released after June 2013.

What you can do is go to this link at Github and download Apple Hardware Test for a iMac model 12.1, place the download on the desktop, connect up a USB thumb drive and drag the download to it. It will make the AHT bootable.

GitHub - upekkha/AppleHardwareTest: Apple Hardware Test Download Links

Apple Hardware Test Download Links. Contribute to upekkha/AppleHardwareTest development by creating an account on GitHub.

github.com

 

[TwoH]

Two common causes I know of for these machines with kernel panic:
GPU issue - it's much more common in the 27" models though.
RAM issue - I find this more likely, and noticed a lot of users here experience issues with OWC RAM.