The problem is that it overheats. I experience graphical artifacts and crashes when I max the system with an intensive game. I took it to an Apple store where they replaced the board but it still overheats. I have tried undervolting the system to reduce overall heat while at the same time manually increasing the fan speed. The problem remains. This thing gets up to 100C easy.
I did some research and found that this problem is common for mac minis and mac portables going back several generations. Apple seems to skimp on cooling under max load. I guess these systems just aren't designed for max usage.
That brings me to the iMac. Has anyone used an iMac for gaming? Any heat issues?