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Very quick and effective

Very quick and effective, and of course everything is super quiet! (11th February 2019 via Trustpilot)
NF-A4x10 FLX 12V 4500RPM 40x10mm Quiet Cooling Fan
69 in stock
(114 customer ratings / 7 reviews)

Noctua NF-A4x10 FLX 12V 4500RPM 40x10mm Quiet Cooling Fan

Noctua's first ever 40mm fan is so features packed there isn't enough room to mention them all here. Read on to find out more.


  1. 40 x 10mm quiet PC cooling fan
  2. Noise level from 12.9 dB(A)
  3. Feature packed
  4. Perfect for proprietary cooling

Featuring advanced aerodynamic design measures such as Flow Acceleration Channels and Noctua's AAO frame, the NF-A4x10 FLX is a highly optimised, premium quality quiet fan in 40x10mm size. Smooth Commutation Drive technology and Noctua's reference class SSO2 bearings guarantee superb running smoothness and excellent long-term stability. Topped off with modular cabling, a Low-Noise Adaptor and OmniJoin Adaptor Set as well as six years manufacturer's warranty, the NF-A4x10 is a premium choice for the highest demands.

Flow Acceleration Channels

The NF-A4x10 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. More info.

Reduced Motor Hub Size

Thanks to its streamlined, compact motor design, the NF-A4x10's motor hub is smaller than with conventional 4cm fans. This allows for more blade surface area and thus contributes to the NF-A4x10's superior airflow and pressure performance.

AAO Frame

Noctua's AAO (Advanced Acoustic Optimisation) frames feature integrated anti-vibration pads as well as Noctua's proprietary Stepped Inlet Design and Inner Surface Microstructures, both of which further refine the fans performance/noise efficiency. More info

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. More info

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. More info

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.

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 NF-A4x10 remarkably quiet even at very close distance. More info

SSO2 Bearing

The NF-A4x10 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. More info

Low-Noise Adaptor for full flexibility

The NF-A4x10 FLX (Flexibility) is supplied with a Low-Noise Adaptor (L.N.A.) that reduces the maximum fan speed from 4500 to 3700rpm so that it can be fine-tuned for superior airflow or maximum quietness.

3 to 2-pin Adaptor and Polarity Protection

The NF-A4x10 comes with an adaptor from 3-pin Molex to the 2-pin connectors used on many graphics cards or network and storage devices. An integrated diode provides polarity protection on 2-pin connections.

OmniJoin Adaptor Set

Many devices featuring 40mm fans use proprietary fan headers, so the NF-A4x10 comes with Noctua's OmniJoin Adaptor Set. Just cut the original fans cable, fix it to the adaptor using the supplied 3M Scotchlok connectors and you can plug the NF-A4x10 to proprietary fan headers! More info

Extensive Cabling Options

The fans short 20cm primary cable minimises cable clutter in typical applications while the supplied 30cm extension provides extended reach when necessary. Both cables are fully sleeved.

Six years manufacturer's warranty

Noctua fans are renowned for their impeccable quality and outstanding longevity. Like all Noctua fans, the NF-A4x10 features an MTBF of more than 150,000 hours rating and comes with a full six years manufacturer's warranty.

SpecificationsNF-A4x10 FLX
Size40x40x10 mm
Screw hole spacings32 mm
Blade GeometryA-Series with Flow Acceleration Channels
Frame TechnologyAAO (Advanced Acoustic Optimisation)
Rotational Speed (+/- 10%)4500 RPM
Rotational Speed with L.N.A. (+/- 10%)3700 RPM
Airflow4.8 CFM
Airflow with L.N.A.3.9 CFM
Acoustical Noise17.9 dB(A)
Acoustical Noise with L.N.A.12.9 dB(A)
Static Pressure1.78 mm H2O
Static Pressure with L.N.A.1.21 mm H2O
Max. Input Power0.6 W
Max. Input Current0.05 A
Voltage12 V
MTBF> 150,000 h
AccessoriesLow-Noise Adaptor (L.N.A.), 3:2 Pin Adaptor, OmniJoin Adaptor Set, 30cm Extension Cable, 3 Vibration-Compensators and 4 Fan Screws
Warranty72 months
EAN barcode4716123314691

Customer Reviews

Noctua NF-A4x10 FLX 12V 4500RPM 40x10mm Quiet Cooling Fan


Absolutely brilliant fan motor, the kit is superb, I used the 2 pin lead as this was a replacement fan. The miniature scotch crimps are superb, no soldering or heat shrink to do. Super, super quiet.


, quiet............

Replaced Netgear fans..


I don't normally write reviews but felt I had to on this occasion. I replaced the two fans in my Netgear GS728TP with these - it now runs silently! Awesome product - will definitely be buying more.



I can't quite believe how quiet this fan is. The only problem now is that I can now hear the air flowing round the case of my once noisy switch. The kits comes with extension leads and plug adapters that mean you can use it in most situations. The lead that slows the fan down a little is also very useful. I'm now tempted to go through all my other boxes now and replace the fans.

Great fan super build


Well today the fan arrived. I was surprised of the quality and build very well made very silent too, the other great feature was all of the accessories that are very well made no complaints. I needed the fan for my CCTV Dvr unit. just the right thing and the tech specialist was very kind and extremely helpful.

A stunning and subtle piece of engineering


A real performance leader. Built like a watch. Both higher airflow and less noise than the respectable YStech it replaces. More than double the MTBF, works out at over 17 years expected life. Anti-vibration built in plus anti-vibration mountings supplied. Multi connector kit to cover every eventuality. Fixing screws. Everything but everything is included. Well worth the higher price!

If you are a Home Cinema enthusiast as I am, who replaces all built-in fans with quieter equivalents, then Noctua has you covered for all your needs.

Transformed Thecus N2100


I popped one of these in a Thecus N2100 and it's been transformed. There are various utilities around to try to control the speed of the standard fan to stop it being quite so noisy, but far simpler to fit one of these. Excellent upgrade.


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