So in fact the 722 might be a better receiver than the 622 overall. If the BCM7412 does better Mpeg4 decompression, then this could be one of the reasons for the BSOD on the 622's when on HD channels.
This makes me wonder if the 722's VC1 chipset is why it will have the ability to receive HD VOD. Perhaps the codec for VOD is WMV? Does anyone know on this? Just curious.