I installed XBMC live onto an older NVIDIA ION system (the series with a 1.6GHz CPU) without any problems. XBMC gave me the 1080p and 720p options for video playback and everything worked fine.
Now I'm trying to install the same thing on a newer NVIDIA ION2 system (the series with an 1.8GHz CPU) (Zotac ZBOX ID41) and all I can get is 1280x720p resolution maximum on the HDMI out. XBMC does not display any higher options and played back video is not really crystal clear.
I'm using the latest XBMC live installed on the hard drive.
Note that on the older system, XBMC shows 720p and 1080p separatly from the 1280x720 and 1920x1080 options, the newer system does not.