As far as I know, only the X1950's use the internal bridre ( hmm... It reminds me of a pretty simmilair system of another brand,.. I just cant get the name of it.. )
(adit: didnt look at the link tough.. that site's blocked here.
i guess it doen't really matter if it's internal or external. it's just weird that ati would only make one model that way. the external type crossfire master cards only have 1 dvi, the internal ones have 2.
)