Buyer beware - Dell mini PCs also have this problem, they run constantly and are clearly audible in a quiet room. The BIOS doesn't have any options to disable or reduce the RPM, software sensors don't see the fan and if you unplug it or try to undervolt it the motherboard panics and doesn't boot anymore. Had to sell mine away.

Otherwise they're a nice piece of kit. Perhaps someone can hack the BIOS to remove the fan protections.