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NF-A4x20 PWM 12V 5000RPM 40x20mm Quiet Cooling Fan AU$20.14
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Noctua NF-A4x20 PWM 12V 5000RPM 40x20mm Quiet Cooling Fan

After the success of Noctua’s NF-A4x10 40mm fans we are delighted to offer the 20mm wide version that offers increased static pressure performance.

Features

  1. 40 x 20mm quiet PC cooling fan
  2. Supports fully automatic PWM speed control
  3. Feature packed
  4. Perfect for proprietary cooling
  5. From 5.5 CFM, 14.9 dBA at 5000 RPM

Featuring advanced aerodynamic design measures such as Flow Acceleration Channels and Noctua’s AAO frame, the NF-A4x20 is a highly optimised, premium-quality quiet fan in size 40 x 20mm. The PWM version sports Noctua’s custom-designed NE-FD1 IC for fully automatic speed control via 4-pin fan headers and comes with a Low-Noise Adaptor as well as an OmniJoin Adaptor Set for easy connection to proprietary fan headers. Its superb running smoothness, reference-class SSO2 bearing and Noctua’s trusted premium quality make it an elite choice for the highest demands.

40x20mm size

Compared to Noctua’s award-winning NF-A4x10, the NF-A4x20 is twice as thick, which allows for increased static pressure performance and makes the NF-A4x20 ideal for demanding applications with high flow resistance.

Flow Acceleration Channels

The NF-A4x20 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.

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 fan’s performance/noise efficiency.

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.

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.

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.

SSO2 bearing

The NF-A4x20 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.

Custom-designed PWM IC with SCD

Supporting fully automatic PWM speed control, the fan uses Noctua’s custom-designed NE-FD1 PWM IC that integrates Smooth Commutation Drive (SCD) technology. By providing smoother torque impulses, SCD suppresses PWM switching noises and thus makes the fan quieter at low speeds.

Low-Noise Adaptor

The NF-A4x20 PWM is supplied with a (L.N.A.) that reduces the maximum fan speed from 5000 to 4400rpm. The L.N.A. can be used either to run the fan at a fixed speed of 4400rpm or to cap the maximum speed when using automatic PWM control.

OmniJoin adaptor set

Many devices featuring 40mm fans use proprietary fan headers, so the NF-A4x20 comes with Noctua’s OmniJoin adaptor set. Just cut the original fan’s cable, fix it to the adaptor using the supplied 3M Scotchlok connectors and you can plug the NF-A4x20 to proprietary fan headers!

Extensive cabling options

The fan’s 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 and a 4-pin y-cable allows the connection of a second fan to the same PWM fan header for automatic control.

6-year manufacturer’s warranty

Noctua fans are renowned for their impeccable quality and outstanding longevity. Like all Noctua fans, the NF-A4x20 features an MTTF of more than 150.000 hours rating and comes with a full 6-year manufacturer’s warranty.


SpecificationsNF-A4x20 PWM
Dimensions40 x 40 x 20 mm
Screw hole spacings32 mm
Connector4-Pin PWM
BearingSSO2
Blade GeometryA-Series with Flow Acceleration Channels
Frame TechnologyAAO (Advanced Acoustic Optimisation)
Rotational Speed (±10%)5000 RPM
Rotational Speed with L.N.A. (±10%)4400 RPM
Min. Rotational Speed (PWM, ±20%)1200 RPM
Airflow5.5 CFM
Airflow with L.N.A.4.9 CFM
Acoustical Noise14.9 dB(A)
Acoustical Noise with L.N.A.12.2 dB(A)
Static Pressure2.26 mm H2O
Static Pressure with L.N.A.1.75 mm H2O
Max. Input Power0.6 W
Max. Input Current0.05 A
Voltage12 V
Voltage PWM signal 5 V
MTBF> 150,000 h
AccessoriesLow-Noise Adaptor (L.N.A.), 4-pin y-cable, 30cm extension cable, OmniJoin adaptor set, NA-AV3 anti-vibration mounts and Fan screws
Warranty72 months
EAN barcode9010018100105
SpecificationsNF-A4x20 PWM
Dimensions40 x 40 x 20 mm
Screw hole spacings32 mm
Connector4-Pin PWM
BearingSSO2
Blade GeometryA-Series with Flow Acceleration Channels
Frame TechnologyAAO (Advanced Acoustic Optimisation)
Rotational Speed (±10%)5000 RPM
Rotational Speed with L.N.A. (±10%)4400 RPM
Min. Rotational Speed (PWM, ±20%)1200 RPM
Airflow5.5 CFM
Airflow with L.N.A.4.9 CFM
Acoustical Noise14.9 dB(A)
Acoustical Noise with L.N.A.12.2 dB(A)
Static Pressure2.26 mm H2O
Static Pressure with L.N.A.1.75 mm H2O
Max. Input Power0.6 W
Max. Input Current0.05 A
Voltage12 V
Voltage PWM signal 5 V
MTBF> 150,000 h
AccessoriesLow-Noise Adaptor (L.N.A.), 4-pin y-cable, 30cm extension cable, OmniJoin adaptor set, NA-AV3 anti-vibration mounts and Fan screws
Warranty72 months
EAN barcode9010018100105

Product Resources

FAQ

  • How do I measure fan size?

    The size of fan you need will generally be determined by the size of the fan fitting position in your PC case. The sizes of all the fans on our website are shown as measured along any one of the fan’s four sides, NOT the distance between the fan’s screw holes! Our most popular fan size is 120mm, followed by 80mm. This isn’t really dictated by customer preference, but more by recent designs of PC cases.

    As for the thickness (depth) of the fan, generally 25mm (1 inch) is by far the most common depth, although smaller fans can have shallower depths such as 15mm or even 10mm. All our fans are 25mm thick unless otherwise stated. If you have any questions about which fan you should order, please don’t hesitate to get in touch.

    If you know the distance between the fan mounting screw holes but don’t know what fan size to order, please see the following table. Note that the mounting hole measurements shown below are taken horizontally or vertically between the holes and not diagonally.

    Screw hole spacings and fan sizes

    32mm between screw holes:40mm fan size
    40mm between screw holes:50mm fan size
    50mm between screw holes:60mm fan size
    60mm between screw holes:70mm fan size
    72mm between screw holes:80mm fan size
    83mm between screw holes:92mm fan size
    105mm between screw holes:120mm fan size


  • I received a small cable (resistor) with my fan; what is it for?

    The resistor cable (also called Ultra Low Noise or ULN cable) is designed to allow the fan to run slightly slower for even quieter operation. The benefit in lower running noise is significant. Although the airflow will be reduced slightly, this usually has minimal effect on PC temperature. We would generally recommend using the ULN resistor cable for best results in almost all circumstances.

  • How can I tell which way the air blows through the fan?

    Hold the fan so that the round fan sticker is facing you. You are looking at the rear of the fan. When you plug the fan in, the air will be blowing towards you. If you want a fan to act as an air intake, then the fan sticker will be facing the inside of the case. Some fans also have two small arrows moulded into their plastic housing - one arrow shows the direction of airflow, and the other (at 90°) shows the direction of blade rotation.

  • Is it possible to use a 4-pin PWM fan or CPU cooler with a motherboard which has only 3-pin fan headers on it?

    Electrically, there is no problem doing this - the fourth pin on the fan cable is used purely for PWM control and is not needed in order for the fan to run. So you can plug the 4-pin fan connector onto the 3-pin motherboard fan header, leaving the fourth pin not connected to anything. The fan will potentially run at full speed, so if you would like to reduce the speed of the fan you will need to adjust the fan speed setting in your BIOS or use fan control software such as SpeedFan in Windows.

    The only other problem to consider is that occasionally, components immediately adjacent to the motherboard fan header can get in the way of the larger 4-pin fan connector, physically preventing connection. This problem also occurs if you try to use an in-line fan speed controller such as the one made by Gelid.

    Another avenue to explore is the possibility of using a bay-mounted fan controller. Several models are available now which provide 4-pin fan headers, so this is an easy way to use 4-pin PWM fans in a PC system which has only 3-pin fan headers on its motherboards. When using this method, you may find it necessary to disable any fan warning settings in your motherboard BIOS, since the motherboard may incorrectly believe that its CPU fan has failed when the fan is connected to a fan controller rather than directly to the motherboard itself.

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