Fan NoiseIn past years, users would accept everything for a little bit more performance. Nowadays, users are more aware of the fan noise and the power consumption of their graphics cards.
In order to properly test the fan noise that a card emits, we use the Bruel & Kjaer 2236 sound-level meter (~$4,000). It has the measurement range and the accuracy we are looking for.
The tested graphics card was installed in a system that was completely cooled passively. That is, passive PSU, passive CPU cooler, and passive cooling on the motherboard and on a solid state drive. Noise results of other cards on this page are measurements of the respective reference design.
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 was conducted at 100 cm of distance and at 160 cm off the floor. The ambient background noise level in the room was well below 20 dBA for all measurements. Please note that the dBA scale is not linear but logarithmic. 40 dBA is not twice as loud as 20 dBA. A 3 dBA increase results in double the sound pressure. The human hearing perception is a bit different, and it is generally accepted that a 10 dBA increase doubles the perceived sound level. The 3D load noise levels were tested with a stressful game, not with Furmark.
Fan noise of the ASUS GTX 670 DC Mini is significantly better than the NVIDIA reference design. It is also better than many fully sized, custom-designed GTX 670s we tested before. It is not nearly as quiet as the ASUS GTX 670 DC II, though.
I would, given the compact form factor, say the card is "quiet" during gaming. But I would have said "could be a bit quieter" when compared to full-sized cards. It would have been easy for ASUS to reduce idle noise levels a bit further as the card runs a comfortable 31°C in idle.