SKU: 80466789075

Noctua NF-A4X20 5V PWM 40x20mm Premium Cooling Fan

Sale price$31.41 Regular price$34.90
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Ships within 48 hours · Estimated delivery Jul 20 - Jul 25

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Description

Noctua NF-A4X20 5V PWM 40x20mm Premium Cooling FanFeaturing advanced aerodynamic design measures such as Flow Acceleration Channels and an AAO frame, the NF A4x20 5V PWM is a PWM enabled 5V variant of Noctuas highly optimised, premium quality quiet 40x20mm fan. The custom designed NE FD3 PWM IC that integrates Smooth Commutation Drive technology and Noctuas reference class SSO2 bearings guarantee superb running smoothness and excellent long term stability. Topped off with modular cabling, the

Featuring advanced aerodynamic design measures such as Flow Acceleration Channels and an AAO frame, the NF-A4x20 5V PWM is a PWM enabled 5V variant of Noctua’s highly optimised, premium quality quiet 40x20mm fan. The custom designed NE-FD3 PWM IC that integrates 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, the OmniJoin™ Adaptor Set and 6 years manufacturer’s warranty, the NF-A4x20 5V PWM is a premium choice for demanding 5V applications that require PWM control.

Being a 5V fan, the NF-A4x20 5V PWM cannot be run at 12V and will be damaged when used with typical 12V power sources such as PC motherboard fan headers

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.

5V PWM version

Many devices such as network or storage solutions use 5 volt 40mm fans with PWM speed control. With the same operating voltage, PWM support and the included OmniJoin™ adaptor set that makes it compatible with proprietary fan headers, the NF-A4x20 5V PWM is ideal for replacing noisy or broken 5V 40mm fans with PWM.

Polarity protection

As many devices using 5V fans feature proprietary connectors, and documentation of the pin alignment may not be available, the fan features an integrated diode for polarity protection. This way, you're on the safe side if you accidentally connect it with reverse polarity.

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.

Custom-designed PWM IC with SCD

Supporting fully automatic PWM speed control, the fan uses Noctua's custom-designed NE-FD3 5V 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.

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.

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.

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.

Technical Specifications

Size: 40x40x20 mm
Mounting hole spacing: 32x32 mm
Connector & pin-configuration: 4-pin PWM
Cable length: 20cm + 30cm NA-EC1 extension cable
Bearing: SSO2
Blade geometry: A-Series with Flow Acceleration Channels
Frame technology: AAO (Advanced Acoustic Optimisation)
Rotational speed (+/- 10%): 5000 RPM
Min. rotational speed (PWM, +/-20%): 1100 RPM
Airflow: 9,4 m³/h
Acoustical noise: 14,9 dB(A)
Static pressure: 2,26 mm H₂O
Max. input power: 0,5 W
Max. input current: 0,1 A
Operating voltage: 5 V
Voltage: PWM signal 5 V
MTTF: > 150.000 h
Warranty: 6 years

Package includes:

  1. Noctua NF-A4X20 5V PWM Cooling Fan
  2. 4-pin y-cable
  3. 30cm extension cable
  4. OmniJoin™ adaptor set
  5. NA-AV3 anti-vibration mounts
  6. Fan screws
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 80466789075

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charscars
Lake Worth, US
★★★★★ 5
Very complete kit
This Kit has everything you need to change your waer pump impellor. It comes with directions that are easy to follow, but there re plenty of videos available to help. The Quicksilver kit is priced well and was delivered quickly.
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Reviewed in the United States on November 13, 2025
E
Verified Purchase
Eric Moore
Fort Morgan, US
★★★★★ 5
Perfect OEM fit
Fixed my impeller on my Mercury Salt Water 115. Best done as a two man job. Lots of videos available online .
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Reviewed in the United States on April 14, 2026
A
Verified Purchase
Aiden
Cuba, US
★★★★★ 4
Fits 2001 Bayliner
This product was definitely different than the original I have a 2001 Bayliner with a 3.0 MerCruiser and an alpha one second GEN drive The kit worked but the bottom gasket had a weird cut different than the original I added a gasket maker just in case (Yamaha Lube) Brand! All in all kit was fine, One thing to note is the directions that come with the kit at least for my version we’re not for the same alpha one second GEN 4 stroke kit that I got they were for a two-stroke in the pictures didn’t look the same as the parts that I had got which is fine but it’s miss leading when you send a 4 stroke kit but 2 stroke 90hp to 200hp alpha one directions! If it craps out this review will change
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Reviewed in the United States on June 30, 2020
A
Verified Purchase
Air Assault
Natrona Heights, US
★★★★★ 5
Super great product. Has the power and functionality to get you repairing fast!
Super great product. Has the power and functionality to get you repairing fast! Fully recommend this and it has worked great since I've owned it. Still going strong in the durability and design looks like it will keep it going strong for many years. Highly highly recommend buying this. Will work in Kuwait, Iraq, UAE, and Saudi. Good for Camps around the CENTCOM area!
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Reviewed in the United States on October 6, 2025
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Verified Purchase
Jed V
Bozeman, US
★★★★★ 5
Solid Product
worked well, easy to install.
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Reviewed in the United States on November 3, 2025

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