You want noisy? Your computer isn't noisy. This clip features one of the Brocade core switches being used for the conference networking at Linux.conf.au being switched on for the first time.
It is extremely loud -- and this is in a test and set-up scenario, not under the full pressure of constant network access by conference attendees. On the other hand (and as commenters below have also noted), you'd typically find this kind of gear in a data centre where other cooling technologies are in place.
The lesson either way? In networking, ear protection is vital.
Whisper silent [YouTube]