I am having the same problem. I have the 2012 15" 8GB MacBook pro. I just got it today so I installed all of the stuff required for it an the heat was minor. Then I installed Diablo 3 and it was fine during installation. When I started playing though, the fan got louder and louder until I quit out of the game after maybe 20-30 mins to let it cool down a bit. So I installed another game that while it was cooling down since there didn't seem to be a problem there. After the fan calmed down and it had cooled off I started playing Diablo 3 again. The fan reached the same loudness as the first time after about the same time, and the computer started to get very hot. I asked someone if this was expected and they said yes, so I continued to play. After about 3 hours, my laptop shut off after increasingly getting hotter. I have an older desk Mac that I have logged more than 6-8 hours straight gaming on a rainy day and did not have this problem. I'm currently waiting for my brand new MacBook pro to cool down, but when it does what should I do and how can I avoid this problem? I'm going to go to the genius bar tomorrow just incase I happened upon a faulty one, but would like to know what I can and should do now.