[Freeswitch-users] FS limit

Hello guys, I am doing some test in my FS box and I found it does not accept more than 300 calls. It is a 12 core E5-1650 Xeon server and I can see in 'top' that FS cpu goes to 140% (over 1200%). Once 300 calls is reached, FS starts responding 480 Temporary Unavailable: http://i.tinyuploads.com/to7Amt.png Do you know where the bottleneck is? I can see low disk activity, low memory consuption... Regards