updated 02:40 pm EDT, Fri September 16, 2011
MacBook Air restricted to single monitor
A new Apple support document reveals restrictions on daisy-chaining the Thunderbolt Display, which is finally shipping to online buyers. Because Thunderbolt supports speeds up to 10Gbps, the obstacle to chaining multiple monitors is less networking than the video hardware in the connected Mac. The MacBook Air can only run one Thunderbolt Display, Apple notes.
All other Thunderbolt-equipped Macs can attach up to two Thunderbolt Displays, with certain provisions. Linking a second Thunderbolt Display to a 13-inch MacBook Pro will cause the notebook's own screen to go black for instance, but a Mac mini using AMD graphics can equip a third monitor at the same time via its HDMI port. The 27-inch iMac supports two Thunderbolt Displays no matter which port arrangement is used.
Apple cautions that Mini DisplayPort monitors cannot be chained off of Thunderbolt Displays at all, even though they can attached to other Thunderbolt peripherals. The company additionally suggests making Thunderbolt Displays the initial hardware in a chain. This should offer the "best performance," it writes.