First of all let’s check out the acoustic measurements for our testing participants and then move on to their cooling efficiency. Note that we are going to list the coolers in ascending order according to their noise measurements on the diagram with the cooling efficiency results. This way we will be able to evaluate them from two standpoints.
If you look at the measurements taken in the most optimal mode, at a 1m distance from the system case, you will see that there are four cooling systems that are the quietest of all. They are Accelero Twin Turbo, Scythe Musashi, Accelero S1 and Radeon HD 4870 reference cooler at the lowest fan rotation speed. Scythe Musashi with both its fans rotating at their maximum speed comes next. And even though the difference between Musashi and Accelero S1 with Turbo-module is only 0.5 dBA, you can clearly hear Musashi against the background of the quiet system case, but not the Accelero S1.
Arctic Cooling Accelero Twin Turbo generating 35 dBA of noise is even louder, although subjectively I would consider this cooler as well as the others before it to be of quiet or medium quiet type, rather than noisy type. However, the noise from the next cooler on the list, Titan Twin Turbo, is no longer within the boundaries of subjective comfort zone. Just like the noise from ATI Radeon HD 4870 reference cooler at 35% of its potential and ~2400 RPM fan rotation speed. The last one in our list is the default Radeon HD 4870 cooler at maximum fan rotation speed that can only be defeated by a powerful hair drier or a vacuum cleaner.