We do not provide assistance with load testing as it is too much of a drain on resources to help people do it properly.  By far the most accurate way is with real traffic.

On May 31, 2016, at 11:46 AM, happy.neko <happy.neko@gmail.com> wrote:

2016-05-31 18:03 GMT+03:00 Michael Jerris <mike@jerris.com>:
On May 29, 2016, at 5:33 PM, happy.neko <happy.neko@gmail.com> wrote:

I know this question is impossible to answer exactly but what roughly estimated CPU usage could I expect for conference with five 480p streams transcoded at 15 fps.
One room with common core i5 quad CPU, 5 simultaneous rooms, 10 rooms?

Correct, it is indeed.  Try it out and see.
 
Will SIPp do the task or your can recommend another (maybe simpler?) benchmark tool?