Noctua fan NF-A4x20 FLX 40 mm, 12 V, 0.6 W, 5000 RPM max, 9.4 m³/h, 32x32 mm mount

The Noctua NF-A4x20 FLX is a premium 40×20 mm computer cooling fan engineered for demanding, space‑restricted applications. With a thickness twice that of Noctua’s 40×10 mm model, it delivers increased static pressure and stable airflow. The FLX variant offers three fixed speed settings (5000 / 4400 / 3700 RPM) via supplied Low-Noise Adaptors and includes the OmniJoin™ adaptor set and extension cabling for easy connection to various proprietary headers and power sources. The fan features advanced aerodynamic measures, a refined SSO2 bearing and Noctua’s AAO frame to ensure long life, smooth operation and low noise.

Advantages

The NF-A4x20 FLX combines Flow Acceleration Channels, Stepped Inlet Design and Inner Surface Microstructures to reduce flow separation and vortex noise while increasing efficiency and suction capacity in constrained spaces. Integrated extra‑soft silicone anti‑vibration pads minimise vibration transmission without affecting compatibility with standard mounts. The Smooth Commutation Drive 2 reduces torque variation and switching noises for exceptionally smooth and quiet operation, and the optimised SSO2 bearing improves stabilisation, precision and lifespan. The kit includes OmniJoin™ adaptors, sleeved cabling, a 3:4 pin adaptor and a 6‑year manufacturer’s warranty.

Suitable for

• Cooling small form‑factor cases and HTPCs with restricted airflow
• High‑resistance applications such as dense heatsinks, radiators or obstructed vents
• Devices requiring connection to proprietary 40 mm fan headers via OmniJoin™

Key specifications

• Model: Noctua NF-A4x20 FLX (MPN: NF-A4X20 FLX, EAN: 9010018100112)
• Size: 40 × 20 mm
• Speed settings: 5000 / 4400 / 3700 RPM (via adapters)
• Airflow (manufacturer data): 9.4 m³/h
• Max. static pressure (manufacturer data): 2.26 mmH2O
• Bearing: SSO2 (self‑stabilising oil‑pressure bearing)
• Voltage: 12 V
• Colour: Brown / Beige
• Included accessories: Low‑Noise/Ultra‑Low‑Noise Adaptors, OmniJoin™ adaptor set, 30 cm extension, 3:4 pin adaptor
• Warranty / Lifespan: MTTF >150,000 h, 6‑year manufacturer’s warranty

How to use

Install the NF-A4x20 FLX in the designated 40 mm fan slot using standard mounting holes or clips; the integrated anti‑vibration pads maintain compatibility with common heatsink mounts. Choose the appropriate Low‑Noise or Ultra‑Low‑Noise Adaptor to set the fan speed to 5000, 4400 or 3700 RPM according to your cooling vs. noise requirements. Use the supplied OmniJoin™ adaptor set to connect the fan to proprietary 40 mm headers by cutting the original cable and securing connections with the included 3M Scotchlok™ connectors. Use the 30 cm sleeved extension or the 3:4 pin adaptor to reach power supply connectors if needed.

Recommendations

For optimal performance in high‑resistance environments, place the NF-A4x20 FLX as close as possible to the heat source and choose a higher speed setting if increased static pressure is required; for quieter operation in less obstructed configurations, use the lower speed adaptors.