I am using x11vnc over 15Mbit/s network with 20ms latency. When the screen is changing a lot x11vnc is slow - for example when I switch a tab in a browser, it takes almost two seconds until the view is fully redrawn.

The strange thing is that max connection speed of x11vnc is even during slow redrawing only about 10% of the available bandwidth. Why is x11vnc not using available bandwidth to speed the redrawing up? For example scp is using 100% of available bandwidth without problems.

How can I identify what is the bottleneck for x11vnc on my system? So far I think:

1. 10% network usage => network is not a bottleneck
2. fb read rate: 601 MB/sec => reading fb is not a bottleneck

Any ideas how can I further profile x11vnc and find out what is causing a slowdown?

For example is there any switch for x11vnc to show how much data it is handling and how long it takes to grab a screen, process and compress it and send it over the network?