First, we'll have a look at power consumption. Note that the numbers I'm presenting subtract the values of a GeForce GT 430 at idle, coming as close as possible to isolating each card's power use.
AMD's new Radeon ties Nvidia's GeForce GTX 650 Ti in this metric. Strangely, it beats our Radeon HD 7770 sample by a few watts.
Specifically, we used Crysis 3 for our load measurement, and it's important to remember that the outcome will certainly vary based on the game you're running.
Thermal readings are, of course, determined largely by the effectiveness of a given board's cooler. Sapphire's HD 7790 Dual-X enjoys a unique advantage in this regard, although we're also impressed that a reference GeForce GTX 650 Ti keeps up.