Noctua NF-A4x20 FLX Premium Fan

Featuring advanced aerodynamic design measures such as Flow Acceleration Channels and Noctua’s AAO frame, the NF-A4x20 FLX is a highly optimised, premium-quality quiet fan in size 40x20mm. The FLX version provides 5000/4400/3700rpm speed settings via the supplied Low-Noise Adaptors and includes the OmniJoin™ Adaptor Set for easy connection to proprietary fan headers. Its superb running smoothness, reference-class SSO2 bearing and Noctua’s trusted premium quality make it an elite choice for the highest demands.

40x20mm size 
Compared to Noctua’s award-winning NF-A4x10, the NF-A4x20 is twice as thick, which allows for increased static pressure performance and makes the NF-A4x20 ideal for demanding applications with high flow resistance.

Flow Acceleration Channels 
The NF-A4x20 FLX impeller features suction side Flow Acceleration Channels. By speeding up the airflow at the crucial outer blade regions, this measure reduces suction side flow separation and thus leads to better efficiency and lower vortex noise.

3 to 2-pin Adaptor and polarity protection 
The NF-A4x20 FLX comes with an adaptor for linking a 3-pin Molex to the 2-pin connectors used on many network and storage devices. An integrated diode provides polarity protection on 2-pin connections.

Inner Surface Microstructures 
With the tips of the fan blades ploughing through the boundary layer created by the Inner Surface Microstructures, flow separation from the suction side of the blades is significantly suppressed, which results in reduced blade passing noise and improved airflow and pressure efficiency.

Stepped Inlet Design 
Noctua’s Stepped Inlet Design adds turbulence to the influx in order to facilitate the transition from laminar flow to turbulent flow, which reduces tonal intake noise, improves flow attachment and increases suction capacity, especially in space restricted environments.

Smooth Commutation Drive 2 
The latest version of Noctua’s advanced Smooth Commutation Drive system ensures superb running smoothness by eliminating torque variations and switching noises. This makes the NFA4x20 FLX remarkably quiet even at very close distance.

SSO2 bearing 
The NF-A4x20 FLX features the further optimised second generation of Noctua’s renowned, time-tested SSO bearing. With SSO2, the rear magnet is placed closer to the axis to provide even better stabilisation, precision and durability.

Integrated anti-vibration pads
Integrated Anti-Vibration Pads made from extra-soft silicone minimise the transmission of minute vibrations while maintaining full compatibility with all standard mounting systems and fan clips used on heatsinks.

OmniJoin Adaptor Set 
Many devices featuring 40mm fans use proprietary fan headers, so the NF-A4x20 FLX comes with Noctua’s OmniJoin Adaptor Set. Just cut the original fan’s cable, fix it to the adaptor using the supplied 3M Scotchlok™ connectors and you can plug the NF-A4x20 FLX to proprietary fan headers!