Power Consumption

On top of our graphics performance testing, we’ve also measured the power consumption of the tested graphics card at both idle and load. For this we used the same systems that we have used for our 3D performance testing.

For our idle testing, we left the cards idling on the desktop for ten minutes, recording the average draw at the wall socket. For load testing, we used our benchmark routine from Crysis in DirectX 10 mode and measured the peak power consumption throughout the benchmark. We tested the cards in a number of other scenarios and this proved to be the most intensive in all cases, so you can consider this to be a worst-case scenario.

Bear in mind that we have disabled all CPU-related power management options in the motherboard's BIOS so that we can highlight exactly how well the GPU's power management features are working (or not).



As we saw with the HIS Radeon HD 4850 IceQ 4 TurboX last week, the Radeon HD 4870 1GB uses less power than the reference card (in this case the 4870 512MB). We were so surprised by these numbers that we re-ran our power consumption tests with the Radeon HD 4870 512MB, only to find that they were indeed accurate.

What's worth bearing in mind here is that power consumption between chips from even the same wafer can be quite different so don't expect the 4870 1GB to magically use less power than a 4870 512MB card - you could find the complete opposite happening. What we can say with a certain degree of confidence though is that AMD appears to be improving power efficiency as the manufacturing process matures.