Power Consumption & Temperatures
Power consumption levels on the ATI Radeon HD 5870 were quite notable. While idle it was the lowest we have seen from a mid-range to high-end graphics card, with a total system consumption of just 148 watts. The next best result was seen from the GeForce GTX 275 with 154 watts, while the Radeon HD 4870 X2 idled at 203 watts and the GeForce GTX 295 at 245.
When gaming the Radeon HD 5870 consumed the same amount of power as the GeForce GTX 260, 343 watts; this is obviously very impressive given how much faster this new Radeon graphics card was in comparison. The test system with the Radeon HD 4870 X2 sucked down an incredible 460 watts while under load, which meant that it required 34% more power than the Radeon HD 5870.
Although the Radeon HD 5870 was light on fuel, it still tends to run quite hot when gaming. Temperatures reached a sizzling 87 degrees, making this one of the hottest graphics cards we tested, almost on par with the Radeon HD 4870 X2. That said, the Radeon HD 5870 ran at just 38 degrees when at the Windows 7 desktop.