Admittedly, because of VNC's age, there are many sub-optimal encoding methods available and many different implementations which might not be fully compatible with each other. So, maybe your chosen server has some good encoding methods available and maybe the client can support some good encoding methods, but the intersection of supported encodings might be bad.
Users of VNC often need to understand how to tweak their settings for the best result. The client should choose the "best" encoding automatically, but this cannot be fully relied upon. On a slow network (like yours), it's probably best to select "tight" encoding, allow lossy compression (jpeg) and turn down the quality a bit.
That is to say, if the implementation that you're using doesn't support h264. Currently, there are not many that do.
Admittedly, because of VNC's age, there are many sub-optimal encoding methods available and many different implementations which might not be fully compatible with each other. So, maybe your chosen server has some good encoding methods available and maybe the client can support some good encoding methods, but the intersection of supported encodings might be bad.
Users of VNC often need to understand how to tweak their settings for the best result. The client should choose the "best" encoding automatically, but this cannot be fully relied upon. On a slow network (like yours), it's probably best to select "tight" encoding, allow lossy compression (jpeg) and turn down the quality a bit.
That is to say, if the implementation that you're using doesn't support h264. Currently, there are not many that do.