Power Consumption & Temperatures
The power consumption of the Radeon HD 7870 was comparable to that of the HD 5870 and HD 6950, this is impressive considering it delivers a lot more performance. With a total system consumption of 324 watts, the Radeon HD 7870 configuration used 14% less power than the Radeon HD 6970 despite being 11% faster at 1920x1200.
The Radeon HD 7850 consumed just 294 watts under load. This is 9% less than the Radeon HD 6950, a card which it was a fraction faster than in most cases.
The Radeon HD 7850 provided remarkably low load temperatures for a reference card. Under load the card never exceeded 63 degrees, which is remarkably low. Armed with the same cooler the Radeon HD 7870 did operate 16% hotter than the HD 7850, but even then it was much cooler than most of the other cards tested.