Power Consumption

We tested the power consumption with a Watts Up? Pro power meter, using the device to record the total system power consumption at the wall socket, while we ran three sets of four runs of Crysis in DX10 at 1920x1200.

Using the data recorded by the meter we could determine the peak output, the consistent minimum and the average load over the entire run of tests.

As both ATI and Nvidia test benches are now identical Core i7 systems, we can accurately determine the apples to apples difference of what power both PCs take to run.


At idle, the GeForce GTX 295 is quite a bit more power efficient than the Radeon HD 4870 X2 - 27.2W or a 12 percent difference is quite considerable, especially because unless you're a hardcore gamer who only uses their PC to game on, a graphics card will probably spend most of its life idle.

Even with quad SLI installed, it still uses less power than a pair of normal Radeon HD 4870 1GBs in CrossFire - that's four GPUs versus two! CrossFireX with four GPUs is some 42W more power hungry than two GeForce GTX 295 in quad SLI as well.


Under load, things are changed and a pair of Nvidia GeForce GTX 295s in quad SLI now guzzle the most from the socket at nearly 675W! CrossFireX isn't far behind at 645W though, however a single GeForce GTX 295 is 38W lower power than a Radeon HD 4870 X2 instead. A single GeForce GTX 295 with its two GPUs is still more power efficient than a pair of GeForce GTX 260-216s and GTX 280s in SLI by 39W and 112W, or nine and 26 percent respectively - that's also pretty significant.


It's the peak power use that was really quite incredible though and also a reason why we ran Crysis for half an hour in order to heat the GPUs up and burn them in a bit - peak power use increased to a point and plateaued in the later runs. At 784W you'll need a 850-1,000W PSU to keep a pair of Radeon HD 4870 X2s in CrossFireX happy, and this it without additional hard drives or peripherals as well. A pair of GeForce 295s in quad SLI were not far behind at 735W, a seven percent difference.

The single cards are also about the same difference at 8.5 percent in favour of the GeForce GTX 295 again, although both will easily require well over 500W from a PSU to be safe.

Just like in the average load value above, the GeForce GTX 295 is more power efficient than two separate, single GPU cards in SLI as well, by eight and 25 percent to the GTX 260-216 and GTX 280s respectively.