Power Consumption

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

• ATI cards

  Intel Core 2 Quad Q6600 (operating at 3.00GHz – 9x333MHz); Asus Maximus Formula motherboard (Intel X38 Express); 2x 2GB Corsair XMS2-6400C5 (operating in dual channel at DDR2-800 5-5-5-12-1T); Seagate Barracuda 7200.9 200GB SATA hard drive; Enermax Galaxy DXX 1000W PSU; Windows Vista Ultimate x86-64 (with Service Pack 1).
  
  

• Nvidia cards

  Intel Core 2 Quad Q6600 (operating at 3.00GHz – 9x333MHz); XFX nForce 780i SLI motherboard (nForce 780i SLI); 2x 2GB Corsair XMS2-6400C5 (operating in dual channel at DDR2-800 5-5-5-12-1T); Seagate Barracuda 7200.9 200GB SATA hard drive; Enermax Galaxy DXX 1000W PSU; Windows Vista Ultimate x86-64 (with Service Pack 1).

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).



Power consumption on the Radeon HD 4870 X2 is very high at both load and idle, but this comes as no surprise to me because you don't get the fastest graphics card in the world without expecting high power draw numbers as part of the package. However, what's a concern for me is the high idle power draw of both this and the Radeon HD 4870.

AMD said it worked hard on power consumption at idle in particular with the introduction of PowerPlay technology onto desktop cards, but it clearly doesn't seem to be working all that well here as both cards consume more power at idle than even Nvidia's GeForce 9800 GX2, which isn't something to be proud of.