NoctuaNF-A4x20 FLX Computer Case Fan - Cooling Components (Computer Case, Fan, 4 cm, 3700 RPM, 5000 RPM, 4400 RPM)
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NoctuaNF-A4x20 FLX Computer Case Fan - Cooling Components (Computer Case, Fan, 4 cm, 3700 RPM, 5000 RPM, 4400 RPM)

4.8/5
Product ID: 47568525
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Details

  • Product Dimensions
    1.57"L x x
  • Brand
    Noctua
  • Power Connector Type
    4-Pin
  • Voltage
    12 Volts
  • Cooling Method
    Air
  • Compatible Devices
    Desktop
🌀5000 RPM max speed
🔇Ultra-quiet 14.9 dB noise level
⚙️150,000+ hours MTTF durability

Description

🌀 Silent power in a compact package — cool smarter, not louder!

  • COMPACT YET MIGHTY - Slim 40x40x20mm design fits perfectly in 1U servers, NAS, and network gear without compromise.
  • PLUG PLAY CONVENIENCE - Includes anti-vibration mounts, extension cables, and OmniJoin adaptors for seamless installation.
  • PRECISION COOLING POWER - Turbocharge your rig with up to 5000 RPM for optimal airflow in compact spaces.
  • VERSATILE SPEED CONTROL - Three-speed FLX settings let you customize performance from near-silent to max airflow.
  • WHISPER QUIET OPERATION - Stay focused with noise levels as low as 14.9 dB—cooling that won’t interrupt your flow.

The Noctua NF-A4x20 FLX is a premium 40x40x20mm computer case fan delivering up to 5000 RPM airflow with ultra-low noise at 14.9 dB. Designed for 1U applications and network/storage devices, it features advanced acoustic optimization, three-speed control via Low-Noise Adaptors, and a robust 150,000+ hour MTTF for reliable, silent cooling in tight spaces.

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Specifications

Compatible DevicesDesktop
Noise Level14.9 dB
Maximum Rotational Speed5000 RPM
Air Flow Capacity9.4 CMPH
Cooling MethodAir
Power Connector Type3-Pin
Voltage12 Volts
Material TypeFibre-glass reinforced PBT
Item Dimensions L x W x H1.57"L x 0.79"W x 1.57"H

Have a Question? See What Others Asked

Whats the cfm of this fan?
14.9dba at what speed?
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What is the mtbf. How many hours of life can I expect from one of these?

Reviews

4.8

All from verified purchases

P**K

Perfect for network switch fan replacement projects - Noctua is an amazing company

I purchased an unmanaged 5 port, 10gbe / 100gbs network switch to put in my makeshift networking closet. Closet is about 6 feet from my work station. Switch works GREAT, but has a 40mm fan that is legit 40db loud on the tech sheet for it but more like 50db in real life which is like having a conversation with a person loud.To remedy the issue, I purchased this fan. The fan itself is of the high quality and acumen for brown color tones one would expect from Noctua, so I'm not even going to touch on that.What is the most amazing about this purchase is everything else it comes with the kit and how Noctua caters to the primary use case for their customers here.My OEM fan has a 2 pin connector to the PCB. Noctua includes a converter so you can splice the OEM 2 pin together with the converter that plugs into the 3 pin coming from the fan. In addition, Noctua provides 3 tool-less (mostly) connectors for the splice. When you crush them down it squirts some kind of non conductive oil into the connections to protect it from water and dust. Made by 3M, but nevertheless a WELL thought out solution to include for their customers.Running at 4000+ rpm is extremely unnecessary for this network switch & since silence is the name of the game for me a way to reduce RPM without implementing a PWM controller in my limited space configuration. Another whammy from Noctua for this problem. Two RPM cables are included that step down the rpm without the need for a separate controller. I used the ultra low noise cable. It reduce the noise some, but the fan itself made such a difference that alone should do the trick for most people.I've purchased a lot of PC components and networking hardware over the years. Not sure I've ever felt like a company thought this much about their customer for something that costs such a small amount of money. The time and frustration they saved me is immeasurable and priceless.Good job Noctua:-)

M**L

Not compatible with some rack mounted conputers

THIS IS A GREAT PRODUCT, but it is NOT going to help reduce the noise of rack mounted hardware.The thing about rack mounted computers and switches is they're intended to be extremely reliable and robust. This means the fan controllers are wired to monitor and maintain speed. This means:1. The wire pinout is different than this product and this fan will not spin.2. Using an adapter to the correct pinout still doesn't make the fan work.3. The hardware fan controlller monitors fan speed and defeats the resistor dongles by increasing voltage to compensate, resulting in precisely the same RPM anyway.My Dell brand switch just sat there with a red light, refusing to boot. Granted, Dell uses propriety connectors for everything to force consumers to purchase only their products, but this is a fan with a standard connector.Plugging this fan into a PC and 3D printer works perfectly and the fan is VERY QUIET compared to other fans it's size.

D**V

Good little fans.

I have bought lots of these over the years, and as is typical for Noctua you're getting a high quality product that is QUIET. I bought these fans to replace the ones on a network switch since I know Noctua is quieter, and while they did not work on the switch I intended them for because the switch is wired different, I used them in another one and they work perfectly.Yes some may say they don't flow as much as the industrial grade, super loud fans that come with them, but in a home environment that matters much less and I'd rather have peace and quiet thanks to Noctua.That being said, this is a small fan, small fans spin faster and are louder by nature, so I'd still recommend either using the included Low Noise Adapter Cable (labeled in the box), or implementing some sort of fan control. At 50% speed these are basically whisper quiet, and move some decent air. I also have the PWM versions of these which are easier to control for speed, but you get the idea.One small con is that the rubber dampener things that come with these are basically useless because they don't seem to stay in on the small fans. I've used them on the 120mm fans and they work fine but for these they don't really work as well and the fan slips off.

Common Questions

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TrustScore 4.5 | 7,300+ reviews

Anita G.

Good experience, but the tracking updates could be better.

2 months ago

Khalid Z.

Great experience from order to delivery. Highly recommended!

1 week ago

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163 Lei

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Trustpilot

TrustScore 4.5 | 7,300+ reviews

Yusuf A.

Fantastic experience overall. Will recommend to friends and family.

1 month ago

Neha S.

Excellent communication throughout the order process. Product is perfect.

2 weeks ago

Noctuanf A4x20 Flx Computer Case Fan Cooling Components Computer Case | Desertcart Romania