I am trying a load on FS. I am making originate call between two FS boxes. Originator endpoint is playing one minute sound file with raw format, the other endpoint is sleeping during this time. I am using Xeon quad X5355, 2.66 Ghz box as originator, the other remote endpoint is hp laptop. The system can handle 500 simultaneous originate calls, successfully, without any NO_ANSWER event. But when I start more than 600 originate calls, the Xeon box is having high cpu utilization (almost 100%) and system almost freezes and getting a lot of no-answer calls. I thought this is due to RTP streams and I made Xeon to sleep instead of playing sound file. But I got same behavior, that means it did not help. I am thinking either there is some thread code block that eats CPU or something else. Could you please guide me so that I can achieve 1000 simultaneous originate calls? I appreciate your help, Best Regards Erol Akarsu