Testing was done with the fans mounted one at a time on a single Swiftech MCR120QP radiator, with the fan controlled using a dedicated fan controller (Aquacomputer Aquaero 6 XT) in PWM mode. 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.
Let’s remind ourselves that the fan is rated for 1150 RPM (+/- 10%). All three fans hit an average of 1138 RPM at 12 V and went down to an average of 187 RPM at 2.4 V before turning off. That is a long 2.4-12 V range of control here, and exceeds the rated 5- 12 V range as well. Your findings may differ and I would love to know about it in the comment section below. The RPM response curve is a bit out of shape owing to one fan being an outlier but this is a good start!
As far as noise and airflow goes, let’s compare the fan with others having max speed in the 801-1200 RPM range:
Have you seen comments online about how fans at the 1000 RPM mark or below are more or less identical? There is some merit to that statement, mostly owing to the part despite good fans continuing to be a certain percentage better than worse fans, the actual difference in performance at lower values is not much and even harder to tell in practice. The same goes here where the Y-axis scales are smaller to help differentiate between the various fans, and even so most are quite close to each other. The main thing to note here is that fan bearing noise is more important a factor here than with higher speed fans, and to many the buzz from ball bearing fans is simply not worth it. Dual ball bearings help, but still those valuing silence over anything else should look elsewhere. The Darkside GT 1150 is a good fan from a performance/noise basis here too, and it’s strongest point is at lower fan speeds where you would tend to have fans at idle. So if you wanted to perhaps extend an “idle” scenario for longer, this would help do the trick.