Testing was done with the fan mounted 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. The results are for a sample size of 1 as only one fan was provided by Cooler Master so please keep that in mind.
This is different in that the fan has a switch to toggle between three modes and max RPM speeds, and so I first charted RPM vs PWM for the three modes. S (Silent) mode is rated for 650 to 1300 RPM and this sample went from 1251RPM at 100% PWM to 654 RPM at 25% PWM. Q (Quiet) mode is rated for 650 to 2000 RPM and this sample went from 1993 RPM at 100% to 665 RPM at 25%. P (Performance mode is rated for 650 to 2500 RPM and this sample went from 2468 RPM at 100% to 677 RPM at 25% PWM. They are all within the +/- 10% standard deviation I allow so all good here. That being said, keep in mind that this is all of 1 fan in the test pool. Also, as with the MasterFan Pro 120 AP, the fan switched off below 25% PWM in each mode rather than continuing to remain at the same fan speed all the way down to > 0 %. Perhaps the current supplied is too low at <25% PWM? I am not sure.
Knowing that the largest operating speed range was in P mode, I measured noise and airflow through radiator for it accordingly. The RPM response curve is linear throughout the 25-100% PWM duty cycle range. As far as noise and airflow goes, let’s see how the CM MasterFan Pro 120 AB (for short) stacks up against other 120 mm fans rated in the 2201-3000 RPM range:
To be fair to Cooler Master, an “Air Balance” fan never sounded like the best fit for a radiator. But then again it doesn’t sound like the best fit for anything. Air coolers perhaps? Not many 120 mm tower coolers that scale with fan speeds to benefit from a 2000 RPM fan, especially one that is reasonably loud. As a radiator fan, and on a radiator with average restriction to airflow, the MasterFan Pro AB disappoints. It is louder than average, performs worse than average and thus comes in among the worse fans tested so far, which does include some very good fans. The MasterFan Pro 120 Air Pressure easily outperforms the MasterFan Pro Air Balance in this particular testing methodology, and so the jack of all trades is showing itself to be a master of none indeed.