Power Consumption

On top of our graphics performance testing, we have also measured the power consumption of Nvidia's GeForce GTX 280 graphics card 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:

• 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).
  

• 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).

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 in this section of the title. 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).



Nvidia made a lot of noise about the GTX 280's idle power consumption and it looks as if those advances have paid off – it's the lowest power consumption we recorded on all of the cards tested. Not surprisingly, the GeForce 9800 GTX has the lowest power consumption at load, while the GeForce GTX 280 has similar power consumption to the Radeon HD 3870 X2.

The granularity of the power consumption is also incredibly fine on the GeForce GTX 280, too – Nvidia says that it can turn off individual TPCs when they're not being used, while other parts of the GPU can be heavily clock gated. In fact, the company claims that there's a third power mode inside GT200 – one is especially for HD video playback, which Nvidia says sits at around 10W above idle.