with regards to the jittery, choppy, jerky video please give us a little more info:
1) which UI are you using? so when in the AV wizard did you pick 'static images', 'OpenGL with overlay' or OpenGL with alpha blending'
2) which driver are you using for hardware acceleration? in Web admin > Devices > Media directors look under 'hardware acceleration' to find the driver name - you should be able to use 'vdpau' with your card (I believe). I have had an issue previously with the 'xv' driver that results in the video getting choppier and choppier with each new video played, this gets better again by reloading the router - I have no idea if this is still an issue.