Hi Guys, Just want some advise on a problem I am getting with my Late 2013 21.5" iMac, when I am playing a games everything will be running fine for about 30 mins or longer until all of a sudden the screen will lock up and freeze. This only happens when i'm playing a games, I am unable to quit the application and I have to resort to turning the mac off on the switch. This is becoming a real frustration, and it would be nice to try and work out what is going wrong, any opinions etc would be great. Thanks --- Post Merged, Jul 31, 2016 --- Does anybody have any possible reasons why this could be??