Fan Noise

In 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.

I have to admit I am positively surprised by the idle fan noise of the ASUS EAH5970. It seems AMD has given this some serious thought and implemented an extremely quiet card in idle that ramps up fan speed as needed. As you will see further on in the review, the low fan noise in idle results in higher idle temperatures - still great in my opinion. Under load the fan ramps up gradually to resemble something like a leaf blower when the card has been fully loaded for a while. It seems that despite all the power saving mechanisms the card still has a serious heat output and this heat needs to go away. Looking at the temps again, they are in the 80° range under load which is a safe choice by AMD. Depending on the maximum temperatures reached you could adjust the fan parameters to trade fan noise for temperature.