NF-A4x20 5V

Very quiet and works great for an NVIDIA K80.

I was skeptical when the price of this fan as so much more than others, boy was I glad I still purchased it! The quality of this fan compared to others is unmatched. This fan works off of a 5V pin from a raspberry pi, which most others do not. You can barely tell the fan is on when listening to it it is so quiet. My Pi is in a 3D printed case and without the fan reaches 190C within minutes. With the fan, the pi has not exceeded 110C once over the course of months. I can not rave enough about this fan.

I used the noctua fan to replace a loud fan in a network switch. The OmniJoin adapter that was included was easily usable and works well. I had to use the anti-vibration fan connectors because the previous fan screw holes were smaller than the noctua fan screw holes. The anti-vibration fan connectors were installed and trimmed, but the network switch case didn't fit properly over the anti-vibration fan connectors. It had to be shoved on, but it worked out. The fan moves a good amount of air, but not as much as the original fan. This is still enough air to keep the switch cool, while being fairly quiet. The fan is still audible (at 5v constant, non-PWM), but I believe this is mostly due to the design of the case, not the fan's fault. The box is a bit overkill and has great presentation, but I would rather the item cost less than have a fancy box. Overall, this is a great product and can make most server gear into home gear. There isn't much for competition of noctua's 40mm quiet fans, so you kind of have to deal with noctua's high prices if you need a quiet 40mm fan.

This fan replaced a ball bearing fan that was too loud for my application. This noctua fan fits the bill, trading off some cfm for a more enjoyable experience I have this connected to my car's usb port in the center console to cool down my phone while it's plugged in for apple carplay

Got this for 3DFX voodoo 3 3000 and it cools it just right.

Original chassis design in switch blocks flow and raises noise from turbulence. The original worn Delta wasn't much noisier when new, but chassis can be modified so this replacement Noctua is quieter. Deltas aren't typically as easy to source. Many unnecessary consumer extras

A quality product at a reasonable price and is VERY quiet

Pros: Extremely quite while moving a ton of air Reliability expected of the brand Love the accessories that come in the box Cons: If you are concerned with waste it does come in a standard size fan box so a lot of cardboard It is a great product as expected from Noctua!

Work great cooling my bit axe solo miners

Love Noctua. I bought this to replace my high RPM fan on my Bitaxe gamma, since the stock fan is so loud (7000rpm). However, it does not meet the performance required to sufficiently cool the Bitaxe at 5000rpm. There is also a PWM version but it's also not recommended since you will likely have to put the fan to 100% anyways. Great fan, great company - just did not work for my specific application.

The product arrived quickly and was well packaged. I purchased this fan to cool down a Raspberry pi B+ which I’m using as a light weight desktop for an entertainment system. The only problem I had encountered is that in certain circumstances the pi would overheat and start to throttle the processor back to cool it down. With this fan running which is barely audible, it cools the Raspberry pi down to 27.8C on idle and I haven’t seen it go up higher than 48C while running as much stuff in the background to push that processor. All in all great fan and I would recommend it to anyone who requires good airflow and quiet operation for their cooling requirements.

I bought this fan to cool a product with a horrible thermal design.If anyone else has bought the "IOGEAR GW4K30KIT Wireless 4K at 30Hz Video Extender with Local Pass-Through" product I strongly suggest you open the case and place one of these fans over the main heat sink on each of the units or kiss about $300 goodbye in a couple of months of operation (read the reviews and you'll see what I mean). It's light enough to that a rubber band is all you need to hold it on the heat sink. All in all a great product and as a bonus this fan comes with a connector that can be soldered to the power cable (which is what I did), an extension cable, mounting screws, crimp connectors, and rubber vibration absorbing mounts. I've included a picture of my IOGEAR hack... Note the use of the supplied connector to splice into the power supply wire to run the fan. I soldered it on and used electrical tape to insulate it. Yes it costs a little more but if you have a working unit it will last many years and when these units work you get a great range and an awesome picture.

Nice fan, had to swap pins for application but quality connector components make that easy.