We measured the level of noise using an electronic noise-level meter CENTER-321 in a closed and quiet 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 card’s fans was being adjusted by means of a controller that changed the supply voltage in steps of 0.5 V.
We’ve included the results of the reference AMD Radeon HD 7970 into the next diagram (the vertical dotted lines indicate the top speed of the fans in automatic regulation mode):
The alternative coolers are quieter than the reference Radeon HD 7970. However, the XFX Radeon HD 7950 Double D Black Edition is not much better than the reference Radeon HD 7970 in noisiness and works at the maximum speed of the fans in the automatic regulation mode. So, we can’t recommend the XFX Radeon HD 7950 Double D Black Edition to owners of quiet computers.
The Gigabyte Radeon HD 7970 Ultra Durable and Sapphire Radeon HD 7970 OC Dual-X are quieter than the XFX and the reference card despite the increased GPU and memory clock rates. Neither of them can be heard against the background noise of the working computer, the Sapphire being 1.5 dBA quieter than the Gigabyte. However, the Gigabyte is ahead in 3D applications because, judging by the diagram, its fans are less noisy. If it were not for its musical chokes, the Gigabyte Radeon HD 7970 Ultra Durable would be the quietest Radeon HD 7970 we’ve ever tested. It’s hard to prefer the Gigabyte to the Sapphire in terms of noisiness, though. They are equal to each other in this respect.
We’ve already measured the temperature of the graphics cards, but now we want to put their results down into a single diagram for comparison:
Well, the comparison isn't correct because the GPU and memory clock rates are different and the GPU voltage is different, too. Moreover, the coolers differ in noisiness. Anyway, we can single out the coolers of the Gigabyte and Sapphire cards for their efficiency both in default and overclocked modes. The XFX has a weaker cooler as is indicated by the results of the overclocked Radeon HD 7950.