Noise And Temperatures
The Ares II’s closed-loop liquid cooler isn't particularly quiet, but it does effectively keep the card cool. That's quite an accomplishment.
We used to measure noise using a regularly-calibrated sound level meter, namely, the SL-400 with data logging by Voltcraft. It only provides good results between a limited frequency range, though. It’s practically useless for frequencies higher than 10 kHz. We needed something else to help us represent the impact of coil squealing. PowerColor's AX7990 6GBD5-A2DHJ Devil13 almost drove us insane with its tinnitus-invoking noise last year. Back then, we decided to use a studio microphone that had been calibrated for our purpose and hung vibration-free. We use the same setup to test Asus' Ares II.
PowerColor would have done better at idle if it hadn’t been for the inductor noise that's above the frequency threshold of modern sound level meters. When the squealing is taken into account, the AX7990 Devil13 ends up in second-to-last place. Together, the Ares' two fans generate a base noise level that's slightly higher than the air-cooled cards at idle.
EVGA's well-built GeForce GTX 690 clearly wins out against the AMD-based competition under a gaming load. It really shows that a pair of GK104s generate a lot less heat than two Tahitis. The noise levels of all three cards remain acceptable, though. PowerColor's AX7990 6GBD5-A2DHJ Devil13 brings up the rear in this metric. And two high-end cards from Nvidia manage manage to beat the liquid-cooled Asus Ares II.
HIS' cooler runs out of capacity under full load, requiring that the card spin up its fans and generating more noise than PowerColor's AX7990 6GBD5-A2DHJ Devil13. Then again, anything above 50 dB(A) is just too loud. EVGA's GeForce GTX 690 is the only air-cooled dual-GPU card that manages to stay under this noise level. Meanwhile, Asus' cooling solution shines.
Most systems don't usually see this sort of workload though, so its relevancy is limited to the folks mining for bitcoins (perhaps not a bad idea right now, given what's going on in Cyprus). Without question, the most important charts are our results at idle and under the influence of Crysis 2.