New memory just arrived (2 x 2GB of DDR800) and it all seems fixed now so seems to confirms it; 2 sticks of DDR800 RAM IS REQUIRED on the Zotac ION boards to be able to use the Nvidia deinterlacers. 1 stick of DDR800 or 2 sticks of DDR667 isnt enough... You also need at least 2GB in order to share 512MB to the graphics chipset.