You should benchmark it against the solutions you are currently using.

Qt VNC Server

yes, is it better than other vnc servers ?

what mean is better for me? It is faster than others and use low data rate.

Do you know any think about that?

It looks like I’ll need some help with the VNC side of things. I also have a question about QtVNC—I tried to integrate it, but when I establish a connection, my application crashes, and I haven’t been able to figure out how to fix it. Is QtVNC faster than other VNC programs?

1 - On my own Windows computer, there were no issues.
2 - With fewer points—almost 1/5 fewer—I saw around 10–11 fps.
3 - With more points, I saw 4–5 fps.

I don’t have any issues with data acquisition here; I’m getting similar speeds in all three tests.

As for the number of points, I’m not rendering all of them anyway—I’m rendering around 4,096 points. For that reason, I don’t think there’s a problem there.

It seems to me that I’m experiencing the usual spectrogram/waterfall issue again.

As for VNC, I’m not sure if the VNC screen refresh rate could be causing any issues. VNC is indeed a slower protocol compared to RDP, but I’m using VNC because I need a lower data transfer rate.

Actually, I’ve made a few changes to the VNC server settings, but unfortunately, I can’t set a fixed screen resolution, for example. Maybe setting the screen to 720p or so might help a bit, but then I might run into issues with the UI.

Does anyone have any suggestions?

Are you sure that it's not the network that is the bottleneck ? VNC is not exactly optimized for in terms of bandwidth. You might also want to check if you can tune the Xnvc server configuration to optimize for your use case.