Our gigabit switch is making an awful noise the last few days. It is the fan that is dying. I have already replaced the fan once. Not much choice for a 40mm 5V fan, I found one that claimed to be low noise; it isn't. The switch is the loudest thing from all the computer equipment.
Previously we had a 16 port Fast Ethernet switch without fan. Not enough ports, and I wanted to play with VLANs. So the upgrade was a "D-Link DGS-1224T Web Smart 24-Port 10/100/1000" switch, nice features, but not enough CPU power for reliable SNMP or STP. However, the VLAN feature turned out very useful, so the number of used ports was suddenly much less.
I give up trying to make this switch quiet. I am getting something new. The Dell PowerConnect 1716 looks promising, matches the usable features of the D-Link, but without a fan. More later.