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.

When I received the card I would not believe my ears. The card was the single loudest graphics card I had ever heard in my life. The card approached noise levels of 50 dbA and kept changing fan speed all the time making it even more annoying. Something was clearly wrong. After contacting PowerColor they sent me an updated BIOS which greatly improved the fan noise in idle and helped a good deal with the fan noise under load. However, the fan speed changes were still there.
These are caused by the fan control algorithm which gets stuck between two temperature levels. For example up to 60° the fan runs at 30% and above 60° it will run at 40%. Now the card hits 60° and the fan speeds up, the fan speed increase reduces temperatures to 59° and the fan jumps to 30% again. This happens more than once per second in some games. ATI has implemented a feature called "Hysteresis" in their fan controller which acts as some kind of delay to eliminate those constant changes.

According to PowerColor engineers the board design does not allow any more improved fan control. I find this hard to believe and will continue to work with PowerColor on solving the problem.

In its current state I consider the card completely unusable because of the permanent fan speed changes.