Fan Noise
In past years, users would accept everything just to get more performance. Nowadays, this has changed and users have become more aware of the fan noise and the power consumption of their graphic cards.
In order to properly test the fan noise that a card emits, we use the Bruel & Kjaer 2236 sound level meter (~$4,000), which has the measurement range and accuracy we are looking for.
The tested graphics card was installed in a system that was completely passively cooled. That is, passive PSU, passive CPU cooler, passive cooling on the motherboard, and on 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 was conducted at 100 cm of distance and at 160 cm over 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.
The HD 7970 Toxic is reasonably quiet in Idle, certainly a good improvement over the AMD reference design.
On the previous page, we saw a huge increase in power consumption. It comes as no surprise that the fan will have to work extra hard to keep the card cool. While fan noise at the normal clock-speed setting is ok, but certainly not quiet, Boost mode increases fan noise even beyond HD 7970 GHz Edition levels, making it sound like a hair dryer. Our temperature testing shows low GPU temperatures of around 70°C, which suggests that the fan's settings are not properly optimized to the cooler's capabilities, or some engineer just wanted to see "low temperatures" in reviews but didn't care about noise.