Review on Noctua NF A4X20 FLX Premium 40X20Mm by Ben Rodriguez

If you own a Ubiquiti USG Pro 4, you know how annoying fans can be when this router is installed in your office or in a place where noise is an issue represents. These Noctua NF-A4x20 FLX fans are the perfect replacement and with the included resistor (lowest voltage) these fans are almost inaudible. My non-scientific test consisted of running the USG with stock fans and then the Noctua fans with my smartphone and the sound meter app placed about 4 inches from the fans. The results don't match Noctua's fans, they are actually quiet (with a low voltage resistor) unless you keep your head close to the back of the USG. The dB rating dropped from 46.5dB to 38-40dB, although I think some other ambient noise in my office (the clock was ticking and the smartphone itself was off) likely affected the second measurement. Still, it was a great buy for the USG Pro 4 and possibly other 1U rackmount hardware. Highly recommended.