Mac Mini 2011 freezes and reboots My Mac Mini (mid 2011) frequently freezes under medium to heavy graphics load (e.g., while using Citrix RDP or playing games). Until today I used to think this was caused by overheating but after a thorough cleaning at the genius bar the overheating is gone for sure but the random freeze remains. Here is a photo of the display when my computer froze.



Any clues as to what may be the issue here?

Edit: I am thinking this is to with overheating because when I place an ice pack on the mini then I can play as much as I want. If I remove the ice pack then it crashes within 15-20 minutes.

Edit2: Shutdown cause is -128 but memory checks out fine in Apple Diagnostics Test.
The image you showed are symptoms of the graphics chip on the logic board failing. 

This requires a hardware repair (replacing the logic board) unless you find a place that would do component level repairs. 

Given it's a 2011 the Apple Store will still be able to help but the cost of the logic board is (last I recall) usually $157.99 Plus tax plus $79 labor. You get 90 days of warranty on the replacement logic board.