Noctua
Noctua NF-A4x10 FLX, Premium Quiet Fan, 3-Pin (40x10mm, Brown)
Bottom line: The Noctua NF-A4x10 FLX ($15.95 on Amazon as of 2026-10-06): 17.9 dB(A) at full 4500 RPM, quiet enough for a bedroom NAS or DVR.
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*Price sourced from Amazon.com. Last updated 2026-10-06. Price and availability subject to change.
Pros & Cons
Pros
- ✓ 17.9 dB(A) at full 4500 RPM, quiet enough for a bedroom NAS or DVR
- ✓ Two Low-Noise Adaptors included to drop it from 4500 to 3700 RPM
- ✓ OmniJoin adaptor set splices into proprietary non-standard fan headers
- ✓ >150,000 h MTTF rating suits always-on 24/7 appliances
Cons
- ✗ Price, stock, shipping and returns are set by the retailer and may have changed since this page was last updated
Manufacturer description
The NF-A4x10 FLX is Noctua's 40x40x10 mm answer to the shrill, buzzing stock fans that ship inside 3D printers, DVRs, NAS enclosures, network switches and routers. It runs on 12V through a standard 3-pin Molex header at 4500 RPM, and the two supplied Low-Noise Adaptors drop it to 3700 RPM when you want near-silent operation instead of maximum airflow. The A-series design does the acoustic work: Flow Acceleration Channels sharpen the airflow off the blade tips and the Advanced Acoustic Optimisation frame integrates anti-vibration pads at the mounting corners. Noctua rates the bearing at more…
SpecPicks Verdict
SpecPicks scored Noctua NF-A4x10 FLX using a rating × review-volume × price-fit model applied to published specs and reviews across the retro cpu coolers & fans category. Noctua's retro cpu coolers & fans lineup sits within the broader category mid-tier; price and specs are the deciding factors over brand loyalty here. Judge it on the specification table and the price rather than on sentiment: check the figures that decide your use case, then put it side-by-side with two or three close alternatives in the Compare tool before clicking through.
Common buyer scenarios for retro cpu coolers & fans of this kind: matching it to an existing build, replacing a failing part, or upgrading from a previous-generation equivalent. Check the spec table below against your current setup — particularly socket / form-factor / power-rating fields — and confirm compatibility on the retailer's listing before purchase. Prices and stock are set by the retailer and may have moved since this page was last updated.
Frequently Asked Questions
Will this fit my 3D printer or NAS that uses a 40mm fan?
It is a standard 40x40x10 mm fan, so it drops into any 40mm mount with 10mm depth clearance. Measure your existing fan's thickness first, since some devices use thicker 40x20mm fans.
Is it really quiet, or just quieter than the stock fan?
Noctua rates it at a maximum of 17.9 dB(A) at 4500 RPM. Adding one of the two included Low-Noise Adaptors drops it to 3700 RPM for near-silent running.
What do I do if my device doesn't have a standard 3-pin fan header?
The box includes Noctua's OmniJoin adaptor set, which lets you splice the fan onto proprietary headers by joining it to your original fan's connector.
Does it come with mounting hardware or do I need to buy screws?
Fan screws and anti-vibration mounts are both in the box, along with an extension cable and the Low-Noise Adaptors.
Can I control the speed from my motherboard?
This is the 3-pin FLX version, so it supports voltage-based control rather than PWM. Speed is set by the supplied Low-Noise Adaptors or by a voltage-controlled header.
Key Features
- Premium quiet fan, 40x40x10 mm, 12V, 3-pin Molex, 4500/3700 RPM, max. 17.9 dB(A), >150,000 h MTTF
- Award-winning 40x10mm A-series fan with Flow Acceleration Channels and Advanced Acoustic Optimisation frame for superior quiet cooling performance
- Ideal replacement for noisy or broken 12V 4cm fans in 3D printers, DVRs, NAS, switches, routers, other network and storage devices, etc.
- 3-pin 12V FLX version can be run 4500 or 3700 rpm using the supplied Low-Noise Adaptors to fine-tune the fan for maximum airflow or near-silent operation
- Includes anti-vibration mounts, fan screws, Low-Noise Adaptor, extension cable and OmniJoin adaptor set for connecting the fan to proprietary fan headers
Full Specifications
| Brand | Noctua |
|---|---|
| Model | NF-A4x10 |
| Voltage | 12 Volts |
| Material | Fibre-glass reinforced PBT |
| Dimensions | 40x40x10 mm |
| Unit Count | 1.0 Count |
| Noise Level | 17.9 Decibels |
| Part Number | NF-A4x10 |
| Material Type | Fibre-glass reinforced PBT |
| Cooling Method | Air |
| Number of Items | 1 |
| Vibration/Rumble | Yes |
| Air Flow Capacity | 8.2 Cubic Meters Per Hour |
| Compatible Devices | Desktop |
| Power Connector Type | 3-Pin |
| Warranty Description | 6 year manufacturer’s warranty |
| Maximum Rotational Speed | 4500 RPM |
| Item Dimensions L x W x H | 1.57"L x 0.39"W x 1.57"H |
| Global Trade Identification Number | 04716123314691, 07123290462549, 07133363436841 |
Ready to buy?
Noctua NF-A4x10 FLX, Premium Quiet Fan, 3-Pin (40x10mm, Brown) is listed on Amazon. Price, availability, shipping and returns are set by Amazon and its sellers — check the listing for current terms. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.
*Price sourced from Amazon.com. Last updated 2026-10-06. Price and availability subject to change.
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