Usually I don't notice the sound too much, the fans are more noticeable in my hearing range. I have a 9600 that I temporarily installed a mechanical drive in the other day. The difference wasn't really noticeable over the fan.

If I wanted to I could go to quieter fans as the 9600 has to be producing less heat. No mechanical HD and a G3 card in place of the 300mhz 604e