Hi,
I have been setting up my 4400r clone card with zoneminder and have gone through all the usual problems and solutions involved in getting the system up and going.
I believe that I have a solution to the issue where the input images shift between cameras and sometime flicker.
The first thing to do which has been thoroughly covered in posts is to disable the V4L_Multi_buffer.
The second thing to do is to make sure that you enter your monitors in order. That is Video0 1, Video0 2, Video0 5. Just make sure they are is numeric sequential order.
I know that the card uses a cross point video matrix switch so it should not matter but it seems to. At least that is my experience. That should enable you to lower the captures_per_frame option and up your fps.
I hope it works for you..
Cheers
Matt