Fan NoiseIn the past years users would accept everything just to get more performance. Nowadays this has changed and people have become more aware of the fan noise and power consumption of their graphic cards.
In order to properly test the fan noise a card emits we are using a Bruel & Kjaer 2236 sound level meter (~$4,000) which has the measurement range and accuracy we are looking for.
The tested graphics card is installed in a system that is completely passively cooled. That is passive PSU, passive CPU cooler, passive cooling on the motherboard and a solid state drive.
This setup allows us to eliminate secondary noise sources and test only the video card. To be more compliant with standards like DIN 45635 (we are not claiming to be fully DIN 45635 certified) the measurement is conducted at 100 cm distance and 160 cm over the floor. The ambient background noise level in the room is well below 20 dBA for all measurements. Please note that the dBA scale is not linear, it is logarithmic. 40 dBA is not twice as loud as 20 dBA. A 3 dBA increase results in double the sound pressure. The human hearing is a bit different and it is generally accepted that a 10 dBA increase doubles the perceived sound level. The 3D load noise levels are tested with a stressful game, not Furmark.
The ASUS GeForce GTX 580 Direct CU II was the quietest high-end card available at that time, so my expectations were high for the ASUS GTX 680 Direct CU II.
I am happy to confirm that ASUS has successfully reduced fan speeds significantly compared to the NVIDIA reference design, which is already reasonably quiet.
However, under load it is not as quiet as the GTX 580 DC II, which ran at only 30 dBA. Given the low temperatures of the GTX 680 it seems to me that ASUS focused more on lower temperatures with this generation. Since NVIDIA's dynamic overclocking takes temperature into account, this will even provide higher performance. Personally I think it wouldn't have hurt much allow a bit higher temperatures in return for lower fan noise.
Nevertheless, the ASUS GTX 680 DC II provides outstanding noise levels given its performance class.