It is motherboard video, yes. I can guarantee that ever component in the systems is identical. I use the motherboard video because it is HDMI and also sends the audio.
One is hooked up to a 1080p Mitsubishi projector and the other a 47" 1080p LG LCD. As far as I know, the software should be nearly identical. I know I installed CCCP and configured it the same on both boxes. Out of every HTPC I have, this is the only one that will not play SD/HD video -- but it should because like I said, it's an identical box.
Is there a common problem with HD video not playing properly? Perhaps there is a bios setting that is problematic--maybe less video memory allocated? I doubt it but will check if you think something like that could be a problem.
Thanks!