meh..you're kinda right...it's not the lack of the need for the composting chip, but of the dongle.
D. Nalasco, ATI - On an x1800, if you plug them in and not have a link and we were to enable a software crossfire mode over PCI Express, we could still get games to work but they’d be 20-30% faster with the second card which is not really that interesting. You’d want 2x or 80% (gains) and to get those we obviously need an interlink. With the x1300 we could get that 80% in games with PCI Express using some optimizations.