I found a better solution for streaming and it is fast
I use ffmpeg to stream my desktop via UDP:
ffmpeg -f avfoundation -i "1" -s 320x240 -r 25 -c:v mpeg2video -preset superfast -pix_fmt yuv420p -tune zerolatency -f mpegts udp://xxx.xxx.xxx.xxx:1234
and on the raspberry pi side, I use omxplayer to play to hdmi. Note, that you do not need X11 or any windows based system. It works like charm for headless raspberries
Here the omxplayer command:
omxplayer -o hdmi --live udp://192.168.178.20:1234
Note that the parameter --live is important for quick processing.
Btw, you need to buy a mpeg2 license for the raspberry pi, which will cost you around 2,8€.