i was one of the source entries, and i entered a 5-minute map just to get a trophy by default. doodle actually tried on his, so he wins by default. i informed ant of this and he agrees, therefore judging of the source entries isnt needed.
check you've plugged in power to the card and everything. it sounds like overheating, but then again my card idles at 50 degrees and runs at about 70, so it could be normal. try a temperature monitor for your entire PC and seeing if any part is hot before it reboots. you shouldn't need to underclock the card.
its V8 supercars 3, its only there because they play it at a LAN i go to, in teams of two, where one guy tries to win, and the other blocks the others from winning.