Review on TRENDnet TPE-1620WS: 20-Port Gigabit PoE+ Web Smart Switch with SFP Slots - Rack Mountable, 30W per Port, 185W Total Power Budget by David Vargas

I have the 16 port version. It features two 40mm x 20mm 9000RPM fans mounted near the center of the PCB. They have variable speed (PWM) depending on the temperature/power of the load. When you turn on the device, they run at full speed and sound like an airplane taking off. After about 40 seconds, they drop to a much slower speed (and quieter) but start to get annoying with the typical roar of a PWM fan running at a lower voltage. Hiding it in a closet is probably fine with most people, but if not, fan noise might be an issue for you.