Power consumption
Smaller dies usually translate to better in-game power consumption. GT 640 Rev 2 matches the Radeon HD 7730's performance but at a much lower energy cost. The takeaway from this graph is that Nvidia's partners will find it easier to construct half-height, almost-silent cards, should they so choose to.
Noise and thermals
Housed in a quiet system, GT 640 Rev 2 is the quietest of the four discrete cards, with the delta between idle and load decibel levels of just 2.7dB. Temperatures remain good, too, as the GPU stabilises at 63°C when gaming.