That's only 204W on the 12v rail for the whole system. Just so you know.
Anyway, I think it's your power supply, and yeah your card is running way too hot for the fan being 100%. Check to make sure your rails aren't fluctuating too much. An easy way to see that is when you boot up, go into the PC health, and if the values for 12v fluctuate greatly, you got a bad PSU. Of course, if they only fluctuate when stressed, then you simply have an inadequate PSU
. You can use a monitoring utility to check the voltages while running something like a windowed game.