We 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 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. Here are the results (the vertical dotted lines indicate the top speed of the fans in the automatic regulation mode):
As you can see, the cooling system of the reference Nvidia GeForce GTX 680 is indeed better than that of the reference AMD Radeon HD 7970. Despite the higher top speed of the fan (5200 RPM with the GTX 680 and 4900 RPM with the HD 7970), the new card is quieter. As we’ve written above, the top speed of the GeForce GTX 680's cooler is limited to 4200 RPM (85% of the fan's full speed). When under continuous 3D load, the speed range of the cooler is 1080 to 2460 RPM with the GTX 680 and 1000 to 2640 RPM with the HD 7970. Thus, Nvidia comes out the winner in this respect as well.
On the other hand, we can’t say that Nvidia’s cooler is really quiet. It was only silent in 2D mode, but as soon as we launched a 3D application we could hear the GeForce GTX 680 against the background noise of our otherwise quiet testbed. The card would grow louder, the longer we tested it. So, if you want a quiet computer, you will have to look for alternatives to the reference cooler.
The base frequency of the GPU is 1006 MHz but it can be dynamically overclocked by 5-10% to 1056/1112 MHz or somewhat higher. We also tried to overclock our card manually using EVGA PrecisionX 3.0.0 Beta 20, checking the card for stability in a few games and two benchmarks.
The Power Target parameter was set at the maximum 132%. After some experimentation, we found that the GPU could be overclocked by 180 MHz (+17.9%) without compromising the card's stability and image quality. The memory frequency could be increased by 1120 (+18.6%), notching 7128 MHz.
By the way, the GPU Boost feature would automatically raise the GPU clock rate up to 1277 or, occasionally, to 1304 MHz.
The GPU temperature of the overclocked card grew from 81 to 86°C, the cooling fan accelerating to 2820 RPM. This is our first experience of overclocking a reference GeForce GTX 680 and we are going to continue our experiments as soon as we get serially produced versions of that card.
We measured the power consumption of computer systems with different graphics cards using a multifunctional panel Zalman ZM-MFC3 which can report how much power a computer (the monitor not included) draws from a wall socket. There were two test modes: 2D (editing documents in Microsoft Word and web surfing) and 3D (the benchmark from Metro 2033: The Last Refuge in 1920x1080 with maximum settings). Here are the results:
The new GeForce GTX 680 is indeed more economical than its competitors and predecessor. The GeForce GTX 680 system needs 40 watts less power under load than its GeForce GTX 580 counterpart and 34 watts less than the AMD Radeon HD 7970 configuration. We can also note that the power appetite of the GeForce GTX 680 doesn’t grow up as much as that of the Radeon HD 7970 at overclocking.