Power, temperature and noise
GeForce GTX 670 has the lowest specified TDP of any GPU in our line-up. This fact is reinforced by the power-draw results in Batman: Arkham City, where the card just about beats out a Radeon HD 7950 in the juice frugality stakes.
Temperatures are reasonable, if not remarkable.
And being the least power-hungry of our bunch means it's also the quietest. Writing from a pragmatic perspective, there's actually very little to choose between any of the single-GPU cards; none are what we would term as loud.