Noctua fan NF-A4X20 5V PWM — 40×20 mm, 5 V, 4-pin PWM, 1100–5000 RPM, 9.4 m³/h

The Noctua NF-A4x20 5V PWM is a compact 40x20 mm cooling fan engineered for efficient, quiet operation in space-constrained computer and electronic applications. This 5V PWM variant incorporates advanced aerodynamic features such as Flow Acceleration Channels and an AAO frame to optimise airflow and static pressure while maintaining low noise levels. The fan uses Noctua’s custom NE-FD3 PWM IC with Smooth Commutation Drive and SSO2 bearings to ensure smooth rotation and long-term stability. Modular cabling, the OmniJoin™ Adaptor Set and a 6-year manufacturer’s warranty complete the package for dependable performance.

Advantages

The fan provides a wide rotational speed range (1100–5000 RPM) that enables precise PWM-based control of airflow and acoustics. Its aerodynamic design increases airflow (up to 9.4 m³/h) and static pressure (up to 2.26 mmH2O) for effective cooling in restricted spaces, while the NE-FD3 PWM IC and SSO2 bearings ensure low vibration, smooth running and durable operation. Built-in modular cabling and the OmniJoin™ Adaptor Set allow flexible installation and compatibility with various 5V systems.

Suitable for

• Small form factor PCs and mini-ITX builds
• Embedded systems and single-board computers
• Router, NAS and network equipment cooling
• Industrial control units and compact electronic enclosures

Key specifications

• Model: Noctua NF-A4x20 5V PWM (MPN: NF-A4X20 5V PWM)
• Dimensions: 40 x 20 mm
• Rated voltage: 5 V
• Speed range: 1100–5000 RPM (PWM controlled)
• Airflow: up to 9.4 m³/h
• Maximum static pressure: up to 2.26 mmH2O
• Bearing: SSO2
• Features: Flow Acceleration Channels, AAO frame, NE-FD3 PWM IC, Smooth Commutation Drive, modular cabling, OmniJoin™ Adaptor Set
• EAN: 9010018100136

How to use

Install the fan in the desired location within the system using appropriate mounting points for a 40x20 mm fan. Connect the PWM cable to a compatible 5V PWM header or controller; the fan will adjust speed according to PWM signal between 1100 and 5000 RPM. Use the supplied modular cables and OmniJoin™ adapters if a different connector type is required. Ensure correct airflow direction and secure cabling to avoid interference with other components.

Recommendations

For optimal performance, place the NF-A4x20 5V PWM where it can move air directly through heat-generating components or vent channels. Use PWM control to balance cooling and noise, and follow manufacturer guidelines for mounting and electrical connections. Regularly check for dust buildup in tight enclosures to maintain airflow and prolong bearing life.