NoctuaNF-A4x20 PWM, Premium Quiet Fan, 4-Pin (40x20mm, Brown)

I don't write reviews here often, but this device really warranted it. We have an NVR for our security system and lately the fans just seemed to louder than usual. I did some research through YouTube and several mentioned replacing the fans for the unit we have and recommended these fans. I was a bit skeptical thinking would it really make that much of a difference and is this something I should even mess with.I decided to give it a try and all I can say is I wish I would have done this sooner. It was quite easy to remove the existing fans and the the new fans are all wired and come with their screws (the original screws were too small). I did have to shave a little plastic off the connector as it is too narrow for the existing. But just a blade from a box cutter did the trick. I connected them, screwed then in place and put the device back together. As soon as I powered up the device... I convinced they were not even working because it was completely silent. I used a flashlight and sure enough, the fans were turning. But they are insanely quiet! It's sad the equipment I purchased doesn't use a quality quiet fan such as this product. I cannot recommend these enough. Super easy to replace and just incredibly quiet.

My NerdAxe miner went from “too loud to have a zoom call nearby” with the old fan, to “I can’t tell if it is on without looking at the screen” quiet with this fan. Besides wonderfully quiet, it speed modulates properly, is nice to look at, and came with accessories for all sorts of mounting/power scenarios. So while not inexpensive, it was worth it!

Why did you pick this product vs others?:Got this to Modify the Polymaker Polydryer which was loud!!!! With this fan, as expected, is super quiet. Perfect mod.

Good fan.

Used to correct an issue with a Cisco switch where the engineers install fans that sound like nails on a chalkboard in a world where Noctua exists.

This product has what I would say the best packaging and labeling I have ever seen. Good god, if only everything was this good. I ordered these fans for a ubiquiti UNVR which had erratic fan howling (fans going at different speeds making a very weird low hum, too loud for an office). I installed these Noctua fans and fan operation is now silent. Thank you to this company.

Quiet and works just right

Noctua has perfected quiet fans, and this one is extremely quiet. It did not work right with my equipment, but it did work as advertised. The issue was my equipment. Would buy again if I knew it would work correctly with my device.