Alright I moved the GPU fan speed up a bit from 35% to 50% and now I'm getting around 32 Celsius. Is there a limit to which I should stop increasing the fan speed?
When it gets too loud for you.
Far Cry 3 at maxed settings is one of the most demanding games, and your card is most likely running at 100% load the entire time. But 80C is extremely acceptable for that card, and poses no danger to any part of your PC. Idle temps of 30-40C are normal, too.