My GeForce GTX 770 (EVGA SC ACX edition) is not being stressed. The game tends to run at the lower/non-boost clock and even with the boost clock, the game itself does not put more than 60% load on my GPU. That contrasts other games, i.e. BF4 and ACIV, which take it up to 100%.
This makes the game lag, of course, and no one likes lag.