If you look on the page(http://pci-ids.ucw.cz/read/PC/1022) that has the rumored Xbox codenames there is also a section with 'Ariel'. Apparently it has a 'Cryptographic Coprocessor':
Wonder why it would have that? For payment info? DRM?
Are not all files downloaded from xbox live/psn encrypted? Intel chips have hardware support I believe, so an AMD chip probably would want to have it to in some shape or form.