Running like a charm
The resource use under mumble is so low that I can't really measure, most I have had in it at once was around 50 people and I still couldn't tell any resources had been used. Mumble automatically scales the bandwidth use per client to match their upload speed, so people like me on 10mbit down 768k up will use about 7kb/s in bandwidth to transmit, while people with higher uplinks will use more bandwidth. You set the max allowed transmit bandwidth in the murmur.ini (default is 72kb/s) but the thing is you could set it at 5kb/s and you couldn't tell a difference in voice quality, it would just transmit about 3ms later than a faster cap.
Sorry for the late response, I forgot about this thread.