Anandtech has discovered that the newly refreshed MacBook Air does not have a full sized Thunderbolt controller, but rather a slimmed down “Eagle Ridge” chip which is only capable of outputting to one external display plus two bidirectional 10Gbps channels. Its grownup counterpart, which is found on every other Thunderbolt-equipped Mac, is able to drive two external displays and has four bidirectional 10Gbps channels. The Eagle Ridge is essentially “half” of a standard Light Ridge Thunderbolt controller, in terms of both size and ability.
Apple would have had a difficult time cramming a full sized chip into the slim Air, and the integrated graphics are only capable of supporting one external display anyway, so users aren’t really being shorted. But, if Apple is planning on producing “MacBook Pro Airs”, users may come to expect the extra output.