During our conversations with AMD on the Radeon HD 6000 series of video cards it was crystal clear that one of the goals in mind was improved performance per Watt.
AMD says they met their design goals as the AMD Radeon HD 6870 uses less power at idle and the same amount as the ATI Radeon HD 5850 at peak load. What is also interesting is that the AMD Radeon HD 6870 has slightly better performance than the Radeon HD 5850, yet has 25% less silicon in use as the die size is smaller.
For testing power consumption, we took our test system and plugged it into a Kill-A-Watt power meter. For idle numbers, we allowed the system to idle on the desktop for 15 minutes and took the reading. For load numbers we measured the peak wattage used by the system while running the OpenGL benchmark FurMark 1.8.2 at 1920×1200 resolution.
Power Consumption Results: The architecture changes that AMD made in the Radeon HD 6800 ‘Barts’ series of video cards is rather amazing. As a single card the Radeon HD 6850 used roughly the same amount of power at idle and load as an NVIDIA GeForce GTS 450 and it crushes that card in the benchmarks. When you run a pair of Radeon HD 6850 video cards in CrossFire you get great performance and the power consumption is still less than a stock clocked NVIDIA GeForce GTX 470! AMD has great power consumption on the Radeon HD 6850, but the Radeon HD 6870 isn’t that far behind. We found that the Radeon HD 6870 uses about 35W more power at load than compared to a Radeon HD 6850, but get this. The Radeon HD 6870 manages to use less power at load than a ATI Radeon HD 5850 or 5870! AMD has done some great stuff here with power management with the Radeon HD 6000 series.