Power Consumption and Noise
We measured the power consumption of systems with different graphics cards (the monitor excluded) using a specially modified power supply at two loads. The typical gaming load was emulated by running two cycles of the Aliens vs. Predator benchmark at 2560x1600 with 16x AF and 4x MSAA. To create maximum load we launched FurMark 1.8.2 (in stability check mode at 2560x1600 with 16x AF) singly and together with Linpack x64 (LinX 0.6.4, 4750 MB, 5 threads). These two programs load heavily the graphics card and CPU, respectively, so we can determine the peak power draw of the whole system and see what power supply will suffice for it (taking the PSU’s efficiency into account).
You can see the results in the diagram:
The power consumption of the graphics cards is proportional to their recommended prices. The more expensive a product is, the more power it demands. Interestingly, the difference between the Radeon HD 6970 and HD 6950 in peak power consumption is about 100 watts in the gaming mode although it should be only 50 watts according to AMD. On the other hand, we measure the full consumption of the whole computer, so some inaccuracies are possible.
We also measured the level of noise using an electronic noise-level meter CENTER-321 in a closed room about 20 sq. meters large. The noise-level meter was set on a tripod at a distance of 15 centimeters from the graphics card which was installed on an open testbed. The mainboard with the graphics card was placed at an edge of a desk on a foam-rubber tray.
The bottom limit of our noise-level meter is 29.8 dBA whereas the subjectively comfortable (not low, but comfortable) level of noise when measured from that distance is about 36 dBA. The speed of the graphics cards’ coolers was adjusted with a controller that changed the supply voltage in steps of 0.5 V.
The results are shown in the next diagram:
The vertical lines show the fan speed range in the automatic mode when the cards were running FurMark: red dotted lines for the Radeon HD 6950, red solid lines for the Radeon HD 6970 and green lines for the GeForce GTX 570.
As you can see, the reference cooler of the GeForce GTX 570 is the quietest one throughout the entire speed range, but its speed is lower, notwithstanding FurMark. Its max speed was only 2430 RPM after 12 minutes of testing. The new Radeon HD 69xx series cards are not so quiet. The Radeon HD 6950 had a fan speed of 2820 RPM and the Radeon HD 6970, as high as 4760 RPM. But as we wrote above, our sample of the latter card seems to have some problems, so we wouldn’t be so sure about the noise level of the reference HD 6970. We can also note that each card was much more comfortable in terms of noisiness under gaming load.