To note some other thing, probably almost half of the noise it makes is by the buzzling or whine or whatever is called. I'll try to get some more load un 5v line to see what it happens.
Back to the Silverstone....
Odd. Mine has coil whine when the PC is off but once powered up, the only noise is from the fan. When I upgrade my PC (soon, I hope), I'll test the fan starting voltage and try my diode voltage drop idea too.
Edit: I found the diode idea being used in the fan controller sticky so it should be a goer