NF-A4x20 PWM

Bought an old 4 bay 1U rackmount NAS from eb** and was shocked how noisy it was. 60+db while building a raid array. So thought not happening and went looking for silent fans, found these and read the reviews and being a Scotsman I was like seriously? for a wee fan like that? and there were 3 system fans and 1 power supply fan. I was aboot greetin. Bought the 4 fans and proceeded to swap them out taking measurements along the way. After replacing the 3 system fans the noise level dropped to a low of 21db and peak of 25db system temp 1degree lower CPU temp 1 degree higher. I then swapped the power supply fan and set the system to rebuilding a raid volume, which is possibly the most intensive thing a NAS is going to do and it is quite happily purring along at a peak of 18 db with a system temp 2 degrees lower and a CPU temp 1 degree higher than factory fitted fans. I should mention that I am using the low noise adaptor cables that come supplied in the fan kit for the 3 system fans. The kit is well supplied with everything you need and gives you options aplenty for extensions and fitting methods. The quality seems to be superb and longevity is backed by their guarantee. I will be buying these fans exclusively from now on and upgrading all fans in my servers. The only nark I would have is the colour! My god it's awful lets have some bright colourful options yellow/black red/black etc, something to indicate that it's a premium high performance fan. Lookswise it definitely needs some cool. Other wise very happy if not skint wee laddie but well worth it.

Epic little fan. Silent at full speed can’t hear it at all. Got it cooling my vrm heatsink. May get another!

I have purchased several Noctua fans of varying types and sizes and was really happy to see that they also make a range of 40mm PWM fans. I purchased the NF-A4x20 fan to replace the fan on an Icy Dock MB996SP-6SB internal 6 bay SATA enclosure. The fan on the enclosure is not only very noisy, but can only be controlled with a switch on the rear of the enclosure and only be set to High, Medium or Off altogther. Like most other Noctua fans I've purcahsed, the packaging is really well designed and the box contains a number of extra bits such as an extension cable, low noise adapter, splitter cable and a few other bits. Installing this fan was a little more involved as I needed to open the Icy Dock enclosure to disconnect the existing fan and as that fan was only 10mm deep I needed some different screws to mount the Noctua fan which is 20mm deep. Now that the fan is installed and connected to a PWM header on my mother board I can control the speed with software. At 2500 RPM (50%) the fan is completely silent and only can be heard slightly when running at 100%. It's a great fan and I'm very happy with it. Although I really like Noctua's products I'm not so keen on the colour scheme, however as this fan is concealed away in my PC and can't be seen then it doesn't bother me at all.

Full declaration i'm a Noctua fan, but not without justification. Who else will provide an AM4 mounting kit posted FOC for a cooler they released in 2009 (NH-D14)? Which until 2019 was running with the original fans! Having switched from a full ATX case with the NZXT H1 i found the thermals to be less than ideal. A Ryzen 3800X combined with a RTX2070 Super meant that there is alot of heat in the case and no active way to get rid of it. A genius on Reddit figured out these fans fit in the back of the chassis and can help expel the heat (no larger fans will fit unless you bolt them to the outside). I've got 3; 1 for the CPU side and 2 for the CPU side. Do they help? Yes, with a reduction of 4-8 degrees. Not alot, but enough to keep the card from tripping over the thermal throttling threshold. They are silent until temperatures from the CPU hit the 70s when they kick in. Yes at 100% they are audible, but it's a high pitch whine. There is the usual Noctua quality, and colour scheme (more Chromax please!). Definitely recommend these if you have an NZXT H1. Some people have gone as far as adding 4 or 5, too many for my liking. Great little fans.

Price is the main con of this product, but in terms of quality, cooling power and noise level still the best option.

The Noctua NF-A4x20 PWM is a premium quality quiet fan with a 4-pin design, measuring 40x20mm in size. Featuring Noctua's signature brown color scheme, this fan is known for its excellent performance, low noise levels, and efficient cooling capabilities. Whether you need it for compact PC builds, HTPCs, or any application requiring a small yet reliable fan, the NF-A4x20 PWM is a top choice to consider. Its PWM function allows for precise speed control, and Noctua's renowned build quality ensures a long-lasting and dependable cooling solution for your system.

Long story short: Can't say how impressed I am with the quietness of this fan. I placed this fan on top of the RAM sticks, so it blows cold air between the RAM sticks, thus lowering their high temperatures. 👉 There was no need to adjust the speed of this fan because even at MAX. speed (5000RPM) - it does not make noise. Pros: ✔ Silent ✔ Focused airflow (meaning straight air path for better dissipation) ✔ Superior build quality / Top notch materials ✔ Many different cables, anti-vibration mounts to fit your needs Cons: ✖ none I will update if I find anything on continuous use. I would recommend this product without reservation to anyone looking for a high-quality fan. Definitely recommended!

You can tell it's a premium product based on the sheer number of adaptors in the box. Its packaged like something from Apple. I had to touch it to check it was moving it is so quiet. The photo shows it zip-tied to my 10G network card whose max temp it's dropped by 20c. Update: bought another one for my 10g switch which was too loud for my home office. Fitted the Noctua which is almost silent and dropped the temps by 10c too!