Noctua NF-A4x20 PWM

A mini case fan

• 40x20 mm size: Compared to the well-known Noctua NF-A4x10, the NF-A4x20 is twice as thick, which increases the static pressure performance. This makes the NF-A4x20 ideal for applications requiring high strength flow.
• Flow Acceleration Channels: The NF-A4x20 impeller is equipped with flow channels on the suction side of the fan. The flow acceleration generated at the tips of the blades creates a more massive, less dispersed suction, thus increasing efficiency and reducing vortex-related noise disturbance.
• AAO frame: Noctua's AAO (Advanced Acoustic Optimisation) frames are equipped with anti-vibration mounts and benefit from exclusive optimisations to push the limits of performance and silence even further: Stepped Inlet Design and Inner Surface Microstructures.
• Stepped Inlet Design: Noctua's Stepped Inlet Design adds turbulence to the incoming flow, allowing a gradual transition from laminar to turbulent flow. This reduces initial noise emissions, improves flow cohesion and increases suction capacity especially in environments where space is at a premium.

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• Microstructured bypass duct: Because the blade tips are close to the inner surface of the duct (characterised by the presence of a microstructure), the flow separation that occurs at the suction level is almost non-existent. This optimisation reduces noise emissions from blade movement, improves airflow and pressure levels.
• Integrated anti-vibration dampers: The integrated anti-vibration mounts, made from extra soft silicone, reduce the transmission of minute vibrations while ensuring compatibility with standard screws and fastening systems.
• Smooth Commutation Drive 2: The latest version of Noctua's Smooth Commutation Drive system ensures smooth operation by eliminating torque variations and switching noise. This makes the fan very quiet, even at close range.
• SSO2 bearing: The NF-A4x20 is equipped with Noctua's well-known SSO bearing. This is the latest generation, which is even more optimised. The SSO2 is equipped with a rear magnet that is closer to the axle for greater precision, durability and stability.

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Designed for performance

• Compatible with PWM automated speed control systems, the fan features the latest NE-FD1 PWM IC, which incorporates Smooth Commutation Drive (SCD) technology. By generating less abrupt torque pulses, SCD eliminates the noise associated with PWM switching for quieter ventilation at lower speeds.
• When the fan is set to a PWM duty cycle of 0%, either via the motherboard or a PWM fan controller, it shuts down. This allows the creation of semi-passive cooling configurations that automatically shut down the fans - to ensure completely silent operation - depending on load and temperature levels.
• The NF-A4x20 PWMs are supplied with a Low Noise Adaptator (L.N.A.) that drops the maximum speed from 5000 to 4400rpm. The L.N.A. is suitable for both fixed speed operation (4400rpm) and for use in flanged PWM mode.
• As many products with 40mm fans have special connectors to connect them, the NF-A4x20 comes with an OmniJoin adapter kit. Simply cut the cable from your original fan, connect it to the adapter using the supplied 3M Scotchlok connectors. You can then connect your NF-A4x20 to the proprietary fan connector.
• The first fan cable is a short 20cm cable to minimise the space required for normal use. The supplied 30cm extension cable will solve any distance problems. Both cables are fully sheathed and a Y-cable (4-pin ) will allow a second fan to be connected to the same PWM terminal for automated control.
• 6-year manufacturer's warranty: Noctua fans are known for their high quality and long life.

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