Testing was done with the fan mounted one at a time on a single Swiftech MCR140QP radiator in a push configuration, with the fans controlled using a dedicated fan controller (Aquacomputer Aquaero 6 XT) in PWM or power (DC voltage) mode depending on the fan used. The controller also enabled RPM readout. Linear airflow was measured using an Extech 45158 Thermo-Anemometer 6″ away from the fan such that it measured the airflow in feet per minute through the radiator. Fan noise was measured in an anechoic chamber of size 5′ x 8′ with ambient noise level ~19 dBA and a sound probe held 6″ away to measure the sound volume in dBA accordingly. The fans were individually tested and the results below are averaged with a standard deviation calculated.
First up, I wanted to map out the RPM response curves to see if there was a significant difference between the fans controlled via PWM vs DC voltage control before measuring noise and airflow through the radiator.
Unfortunately, this PWM control issue wherein there is a massive drop in fan RPM going from 100% PWM duty cycle to even 99% PWM duty cycle on the Aquaero 6 is not new and it has been covered in more detail here. The situation is still unclear at this point, but what is clear is this: some PWM controllers and the be quiet! Silent Wings 3 PWM fans do not get along very well. This can be remedied if you are handy with electronics and electrical engineering, or simply know someone who does. Thanks a lot to Overclock.net community member Darlene and her “Diva Adapter” I was able to test these fans again with an external pull-up logic in place:
As we saw with the other SW3 fans, an external pull-up helps. I am not an electrical engineer by trade nor will I pretend to understand exactly what is going on, it is for be quiet! to do so. But at this point, I will still suggest sticking with the voltage control versions unless you are aware of these potential, and I have to stress potential here as your motherboard PWM control setup may work just fine, control issues and want to go ahead.
Voltage control was more as I expected. Max RPM was 1590 at 12 V and both fans went down to 456 RPM at 4.2 V before shutting down. In fact, the fans shut down at 4.1 V and turned back on at 4.3 V so the claim of these fans having a low re-starting voltage is true. The RPM response is also very linear and only drop down at the last data point. There was also next to no sample to sample variability here (< 1%) which was nice to see. As such, I chose the DC version for noise and airflow measurements as well as fan comparison.
With the individual fan measurements done, let’s see how it compared with other 140 mm fans rated in the 1201-1800 RPM range.
Overall, another good job by be quiet! As we saw in the case of the 120 mm High-Speed version, this too fares relatively best below 9 V or so from an airflow/noise basis. There is a definite performance increase going to higher speeds, and it holds its own from a pure performance basis as well but gets louder than I imagine most fans of be quiet! would prefer. Not as good as the 120 mm version did but still worthy of consideration.