Multiple screen casting via video streaming can be a heavy load on a network. 

To experience ViewBoard Cast with multiple screen sharing with a reliable signal, we suggest the minimum Wi-Fi signal strength is not lower than -60dBm and the minimum bandwidth recommendation is 1 MB/s (Still picture < 100KB/s, Peak value of a dynamic picture is about 1 MB/s).

If there is still a latency issue, please reduce vCastSender to not exceed two (2) devices for the best performance.