Noctua NF-A12 and P12 Redux Fan Group Test Review - Airflow performance

Airflow performance

On the previous page, you have been able to see the acoustics per fan configured at a selection of three settings. We'll now place a focus on airflow, and while a totally precise measurement, I'll classify this page as somewhat subjective. But we can get a good indication of airflow per fan at each setting.

With the help of a simple to use Anemometer, we can see how airflow behaves. An anemometer is a device used for measuring the speed of the wind, and actually also is a common weather station instrument. The term is derived from the Greek word anemos, which means wind, and is used to describe any wind speed instrument used in meteorology. It's a relatively cheap device to get and does seem to provide pretty steady results. Each fan is measured with the Anemometer positioned precisely as shown above. Now we can measure how much air the fan is sucking inwards, the value is measured in meters per second, higher is in this metric better, of course. 

We start off with 4V with the ULN adapter again. As you can immediately spot, the two (extremely silent) low RPM fans so perform the worst, starting at 1 meter of airflow (BFT) for the Redux 900 followed closely by the A12X25 ULN. The best performer running upwards to 1.7 m/s is the A12X25 FLX. At this low voltage setting, the higher the number the better. You'll notice immediately that the two A12X25 fans actually are already in the lead here. But let's move to more normal settings applied.

Yeah, interesting - the ranking hardly changes much in the ranking with normal voltage settings. That FLX is seriously pushing move serious airflow. 

And again, ranking wise all things remain roughly the same, at 12V the FLX was able to move 3 meters of air per second. These charts here are important, as all fans get the same amount of voltage, and here you can see what fan offer the best airflow. Let's move to the next page and see what effect the fans have on the thermal performance of the cooler.