[Freeswitch-users] Video conference with transcode mode is not working more than for 5-6 users

OS: CentOS 7.2.1511 Freeswitch: 1.6.17 Steps: 1) create video conference (mod_sofia and conference-mode = transcode) with one video stream from conference owner 2) add 4-6 members in this conference who will receive owner's video stream 3) everyone in this conference will see dramatic degradation of video stream (incoming video stream bitrate falls from 1 Mbps to 0.5 Mbps, frame rate falls down to 10 fps from 30 fps, lag between video and audio stream appears) But I don't see any problems with CPU, memory or network. So does anybody knows whether it is an issue or it's how freeswitch 'transcode' mode should works? And what to do to tune performance of this mode?