Hello I have a Dell Poweredge / Dual 3.2 GHZ XEON / 2GB ram running asterisk It's configured using realtime-extensions / sipfriends / iaxfriends (to a local mysql daemon), 80% of all calls are IAX <-> SIP calls with no codec transcoding and no jitterbuffering, and 20% of all calls are IAX <-> IAX native transferrred calls, again no codec translation.. the box has NO zap channels Now, when I have a load of 100 simultaneous users calling (that means I have 200 simultaneous lines open of IAX and SIP calls (where 80% of those calls are IAX calls translated to SIP/RTP) then asterisk uses an average of about 30% to 35% processortime (divided over the processors) and mysqld then using about 1% average load .. so the maximum callers I can have is about 300 .. This CPU load is that mostly generated by handling all those callsetups or is it mostly generated by the IAX -> SIP+RTP proxying(translation?) and some IAX -> IAX native bridged calls? how can I finetune this making one box to handle more simultaneous lines? will faster CPU's work? (3.6 ghz won't help much huh :) will 64 bit cpu's work? (The ones I use now are 32 bit xeons) will MORE (4) CPU's work? will something else work? is this ONLY a cpu problem or is there more I have to take a look at?? Memory speed etc? all ideas apprecieated. Thx. Niels