Fan Noctua 40x40x20mm 5V PWM - NF-A4x20-5V-PWM

This is a 40 mm fan Noctua NF-A4x20-5V-PWM – a compact, 5 V, PWM-controlled fan for situations where space is limited, and you need reliable and quiet cooling. With dimensions of 40 x 40 x 20 mm and a range of 1100 – 5000 RPM, it is a flexible choice for small cases, SFF systems, routers, network devices, or any custom projects. It operates at 5 V, making it convenient for integration into systems where 12 V is not available or practical. Typical of Noctua, the focus is on low noise and long life.

What you get

With PWM control via a 4 Pin connector, you can control the RPM from quiet 1100 RPM to maximum 5000 RPM, allowing you to balance between noise and cooling according to the load. The thickness of 20 mm (compared to the more common 10 mm in this format) allows for better static pressure and more meaningful airflow – up to 5.53 CFM / 9.4 m3/h, which is fully adequate for targeted cooling of chips, VRM, NAS enclosures, or mini-ITX cases. The noise level of 14.9 dBA is very low for this size, so you won't get annoying high-frequency whine, which is typical for small fans. The consumption is only 0.5 W at 0.1 A on 5 V, so the load on the power supply or controller is minimal. The SSO2 Bearing and declared MTBF 150,000 hours make it suitable for 24/7 operation.

• Compact size 40 x 40 x 20 mm, suitable for tight spaces, SFF cases, and specialized devices.
• RPM range 1100 – 5000 RPM, giving you flexibility between quiet operation and more aggressive cooling when needed.
• Airflow up to 5.53 CFM / 9.4 m3/h, sufficient for local cooling of components or small volumes of air.
• Low noise level 14.9 dBA, so even at higher RPMs, the fan remains unobtrusive.
• Operates at 5 V with a consumption of only 0.5 W and current 0.1 A, convenient for low-voltage devices and controllers.
• 4 Pin PWM connector for precise RPM control via motherboard, controller, or external PWM module.
• Bearing SSO2 Bearing and MTBF 150,000 hours, ensuring long life and reliable 24/7 operation, backed by 72 months warranty.

Who is this fan suitable for?

This fan is a good choice if you are doing a compact build, working with network/server equipment, NAS, or need quiet cooling for small electronic devices at 5 V. It is also suitable for modders and DIY projects where size and PWM control are critical. If you need strong airflow for a large case or radiator, the 40 mm form factor is generally not optimal.

The combination of 5 V power supply, PWM control, low noise, and high-quality bearing makes this Noctua 40 mm fan a very sensible choice for serious yet compact systems that need to operate quietly and for a long time.