Fan NoiseIn the past years users would accept everything just to get more performance. Nowadays this has changed with people being 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 Solid-State HDD.
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.
ASUS did an excellent job with the fan settings on their EAH5850 TOP DirectCu. The fan is barely audible in idle and ramps up just slightly under load, just enough to handle the added heat from 3D rendering. Temperatures are in a good range, too, so this seems to be the optimum solution given the heat output and cooling capacity of the heatsink.
When I first received the card from ASUS, the noise levels were acceptable but not too pleasant. After a few quick emails they sent me a new BIOS which delivers the results below. These fan settings will also be used on all production models.