Noctua
Noctua NF-A4x20 5V, Premium Quiet Fan, 3-Pin, 5V Version (40x20mm, Brown)
Bottom line: The Noctua NF-A4x20 5V: 5000 RPM at only 14.9 dB(A) via Advanced Acoustic Optimisation frame; main trade-off: 5V 3-pin only, so it will not run correctly off a 12V motherboard header.
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Pros & Cons
Pros
- ✓ 5000 RPM at only 14.9 dB(A) via Advanced Acoustic Optimisation frame
- ✓ 40x20mm thickness moves more air than standard 10mm-thick 40mm fans
- ✓ Rated >150,000 hours MTTF for always-on NAS, router and DVR duty
- ✓ Ships with anti-vibration mounts, screws, extension cable and OmniJoin adaptors
Cons
- ✗ 5V 3-pin only, so it will not run correctly off a 12V motherboard header
- ✗ 20mm depth can foul tight 1U chassis designed for 10mm fans
- ✗ Brown-and-beige colorway clashes with most modern builds
- ✗ No PWM support, so speed control needs the bundled low-noise setup
SpecPicks Verdict
SpecPicks scored Noctua NF-A4x20 5V 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.
Key Features
- Premium quiet fan, 40x40x20 mm, 5V, 3-pin Molex, 5000 RPM, 14.9 dB(A), >150,000 h MTTF
- Award-winning A-series design with Flow Acceleration Channels and Advanced Acoustic Optimisation frame for superior quiet cooling performance
- 40x20mm size ideal for 1U applications or replacing fans in network and storage equipment (routers, switches, NAS etc.) or other devices such as DVRs
- 5V 3-pin version (5000rpm) for 5V-based industrial applications or replacing 5V fans in various devices
- Includes anti-vibration mounts, fan screws, extension cable and OmniJoin adaptor set for connecting the fan to proprietary fan headers
Full Specifications
| Brand | Noctua |
|---|---|
| Model | NF-A4x20 5V |
| Voltage | 5 Volts |
| Material | Fibre-glass reinforced PBT |
| Dimensions | 40x40x20 mm |
| Unit Count | 1.0 Count |
| Noise Level | 14.9 Decibels |
| Part Number | NF-A4x20 5V |
| Material Type | Fibre-glass reinforced PBT |
| Cooling Method | Air |
| Number of Items | 1 |
| Vibration/Rumble | Yes |
| Compatible Devices | Desktop |
| Power Connector Type | 3-Pin |
| Warranty Description | 6 year manufacturer’s warranty |
| Maximum Rotational Speed | 5000 RPM |
| Item Dimensions L x W x H | 1.57"L x 1.57"W x 0.79"H |
Ready to buy?
Noctua NF-A4x20 5V, Premium Quiet Fan, 3-Pin, 5V Version (40x20mm, 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.
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