There are some key features present in all of the fans we are covering in this review so we’ll cover them off here. These features are not exactly ‘new’ in that Noctua has already implemented them in the larger NF-F12, NF-A14, NF-A15 with good results.
Flow Acceleration Channels
On the curved side of the fan, there are 3 raised stripes on the end of each blade. These are the “Flow Acceleration Channels”, designed to speed up the airflow at the outside of the blades and improve efficiency and noise by reducing “suction side flow separation”. What is suction side flow separation? Fans without these Flow Acceleration Channels can encounter a scenario where the air can ‘leak’ from the tips of the blades and disrupt the vortex, making them inefficient and creating wind noise. By speeding up and directing the airflow as it leaves the outside of the blades, this disruption and noise is reduced. Noctua explain it better on their website with the following graphic.
Advanced Acoustic Optimisation Frame
This was the first thing we spotted when looking at the review samples. The Advanced Acoustic Optimisation (AAO) Frame has the anti-vibration pads, stepped inlet design and inner surface microstructures. The stepped inlet adds turbulence to the intake in order to reduce tonal intake noise, improve flow attachment to the frame and increase suction. This results in less vibration being transferred through the chassis whilst providing a higher airflow through the inlet because the air hugs the frame. The creation of a “boundary layer” of air via little dimple microstructures assists with the reduction of the “suction side flow separation” we mentioned earlier. So these technologies all combine to reduce the ‘wind’ noise and at the same time, increase the airflow. Here are the Noctua diagrams below illustrate the engineering specifics of the frame a little better.
Bearing
The previous technologies work together to reduce wind noise and vibration whilst improving airflow efficiency but it doesn’t stop there. Noctua also implemented the SSO2 bearing where the rear magnet is located closer to the axis to be more stable and precise than the previous SSO. They implemented an oil-based hydrodynamic bearing instead of using traditional ball or sleeve bearings. This also increases durability due to less variation at the core of the spin. Like the NF-F12, NF-A14 and NF-A15, these fans also feature the Smooth Commutation Drive 2 technology that negates the torque variations and switching noises. Noctua back these fans with a 6 year warranty and rate the Mean Time Between Failures at 150,000 hours.
Summary Table
