Power Consumption & Temperatures
The Radeon HD 7770 is very efficient, consuming slightly less power than the HD 6750 and considerably less than the HD 6770 -- impressive given it was 26% faster on average. The HD 7750 cut electricity bill further, and although it was 2% slower than the GTX 550 Ti on average, it used 27% less power.
With its upgraded cooler, the HIS Radeon HD 7750 maxed at 64 degrees under stress in FurMark, which is the same temperature reached by the Gigabyte GeForce GTX 460. The majority of low-end to mid-range graphics cards operated at around 60 degrees, so nothing there's out of the ordinary here.
On the other hand, AMD's Radeon HD 7770 reference design got quite hot at 81 degrees. We should note that at this temperature, the graphics card fan didn't make any more noise than the chassis fans. Additionally, the HD 7770 is one of the few products using a reference cooler in the above graph.