Noctua NF-A4x20 FLX, High-Performance Quiet Fan 40mm

Very good quality, super quiet and efficient, very good value with every connector included .

The Noctua NF-A4x20 FLX is a premium quiet fan known for its exceptional build quality and performance. Designed with advanced aerodynamic engineering, this 40x20mm fan provides efficient cooling while maintaining low noise levels. Its 3-pin connector ensures broad compatibility, making it ideal for a variety of applications, from computer cooling to DIY projects. Users appreciate its robust design, long lifespan, and the inclusion of multiple mounting options. Overall, the NF-A4x20 FLX is a top choice for anyone seeking a reliable and silent cooling solution.

I bought a POE switch (Drayek 1282 to be exact) - I had plans on mounting the switch to the wall behind my desk. I work in data centres a lot, so it shouldn't have surprised how loud the thing was. I took a gamble and bought a couple of these fans. The swap out was very easy - most PC kit will want a 12v fan (in case you were wondering to go with the 5v or 12v variant). The fans ship with everything you could need. My OEM fans connected to a 2 pin header on the main board. I cut the connectors from the old fans and used the included "OnmiJoin adaptor kit" to hook the new Noctua fans up to the original connectors. Again very easy. Mounting the fans in the chassis was easy as well. On power up the drop in noise was significant. Degrees of magnitude quieter. I ran for a day to check switch temperatures were staying low - all good. With that working well, I cracked open the switch again and added the (included) low noise adaptor - this just slows the fan RPM down a bit to reduce the fan noise. Again noticeable difference. Am now at the stage where the switch is under my desk and I can't hear it above the background noise anymore. Bearing in mind that with the OEM fans the noise levels were at the "extremely annoying " level on the other side of a closed door. Very happy - just wish I'd videoed the whole process.

nice product

If you have a flex PSU for pc building ; especially in a SFF build. This totally transformed the fan noise This is the best upgrade for a flex PSU The standard fans with my flex PSU sounded like a jet engine This takes the level below CPU fan noise level Pc case was a jonsbo nv10

I've used Noctua fans before and have always been impressed with them, and this NF-A4x20 FLX certainly didn't disappoint in terms of quality. It's a very well-made little 40mm fan. It runs smoothly, is impressively quiet for its size and feels like a much higher-quality product than many of the generic small fans available. The included accessories are also useful and typical of the attention to detail I've come to expect from Noctua. Unfortunately, after trying it with the project I'd bought it for, I realised it wasn't going to suit my particular setup, so I ended up returning it. That's entirely down to my use case rather than a problem with the fan, which is why I don't think it would be fair to give it a poor rating. If the dimensions, voltage and airflow characteristics match your particular project, I'd have no hesitation recommending it. It's a great little fan — it just wasn't the right one for what I was trying to do.

Very quiet fan, happy with it

Bought as replacements for an old and noisy Netgear network switch. They don’t have the right speed sensing signals that the switch is expecting, so it displays “fault” against them but I knew that before purchasing so isn’t an issue for me. The main improvements as you would expect is the noise, they are significantly quieter than the ones being replaced which you could hear from a different room, but still move a decent amount of air and keep the switch at a good temperature. Does everything you would expect of a fan, and everything you would expect from a Noctua fan in particular.

I bought a new TP-Link Switch and it was ridiculously noisy. I mean, I get that its supposed to live in a server room but surely they could've done something to tone it down a bit. Two of these to replace the ones inside the switch have made it almost silent while still providing sufficient airflow.

I have replaced stock fans from my Unifi Ubiquiti USG Pro and I here the sound barely, before with stock fans I mom used to complain about noise while she was in other bedroom. Now no sound from the fans at all, for your reference I am not using any low noice adaptors. I will purchase two more to replace in 24 port PoE switch.

Works great in my switch, way quiter and moves the same amount of air.

Great silent fan! Works very well for replacing loud fans on flex atx power supplies

Lo ocupe para proyectos de electrónica y la verdad me a ayudado demaciado, me encanta que traiga demás conexiones para su configuración y entre otros más. Sinceramente muy buena marca Noctua.