The amount of noise produced by the coolers was measured throughout the speed range of their fans according to the method explained above. You can see the results in the following diagram with table:
As you can see, the coolers included into this test session do not differ much in terms of noisiness. The Alpenföhn Nordwand is the quietest of the four, its fan working smoothly throughout the entire speed range. The EVGA Superclock is quieter than the Swiftech Polaris 120 but changes its fan speed rather abruptly whereas the Polaris 120’s fan behaves in a steadier manner.
It’s hard to tell what exactly prevented the Swiftech Polaris 120 and the EVGA Superclock from doing better in my tests because their heatsinks represent a very thought-through design with cleverly positioned heat pipes, optimized air flow, and the best-ever implementation of the direct-touch technology. The number of heat pipes (8 millimeters in diameter, by the way) seems sufficient, too. So, I can only see one downside about the new coolers. Their heatsinks have a small overall effective area, which makes the coolers dependent on the speed of the fan. With the fan working at full speed, they delivered high performance, beating the best product from the previous generation of direct-touch coolers.
The type of the heat pipes may be another issue. Zalman and Thermalright have been working on that and Zalman’s recent products deliver unexpectedly high performance (for their design) whereas Thermalright is in fact the leading maker of air-based CPU coolers. I guess the original manufacturer of heatsinks for Swiftech, EVGA and other brands should do something about the heat pipes, too. Until that, we'll be getting good, but not exceptional, coolers like the two new ones discussed today.
Having a somewhat lower recommended price, EVGA Superclock seems preferable to Polaris 120, as it is also quieter and prettier, but its fan is capricious in PWM mode and not stable at low speeds. The choice is yours as always, though.