obviously it DOES need a Pci-X 16 bus.... all PCIX grafix cards are X16 only , it would be more popular among OEMS like Dell... 256 or even 512 system RAM is cheaper than 128mb of high speed graphics memory . The prices won't drop all that much but there will be big saving in the long run for Dell , alienware, HP etc.
The idea is... instead of 256mb of VRAM for the next POS system , 128 , and 256 more system Ram, and a few dollars in the pocket of whatever company sells it . It will look impressive on paper too , systems using it will have alot more RAM, and so the computer illiterate will jump after it .