Apple has posted a support article to clear up potential confusion about the capabilities of its new Thunderbolt-enabled Cinema Display. First of all, it should go without saying that only Macs with a Thunderbolt port will be able to utilize the display to its fullest capability. Fortunately, virtually all new Mac models released in 2011 feature the new I/O port.
Not all Macs' Thunderbolt ports are created equal, however. While most Macs will be able to drive two Thunderbolt displays from a single port, the MacBook Air is only capable of driving a single display. Additionally, the 13-inch MacBook Pro's display will automatically go black if it's driving two Thunderbolt displays; Apple notes this is "expected behavior." The 15 and 17-inch MacBook Pros and iMacs should be capable of driving two displays in addition to their own internal LCDs. The Mac mini can drive two Thunderbolt displays plus a display connected via its HDMI port, but only if the mini has an AMD graphics card.
Apple's notes one other caveat about the Thunderbolt display: older Mini DisplayPort displays won't light up if they're hooked directly into the Thunderbolt port on the newer LCD. Macworld's testing found that Mini DisplayPort LCDs can be added to a Thunderbolt chain and work as normal by hooking them into another Thunderbolt peripheral. It's unclear why simply hooking the older monitors directly into the newer ones doesn't work. For best performance Apple recommends hooking the Thunderbolt display directly into the Mac's port, then hooking Thunderbolt storage devices into the display's relevant port.
Macworld's first look at the new Thunderbolt Display makes it sound like an impressive piece of work; not only is it a huge and vibrant screen, it's also a very powerful hub thanks to the inclusion of three USB ports, Firewire 800, Thunderbolt, and Gigabit Ethernet. That's so many connectivity options that many users may find they're able to funnel everything into their Macs via the Thunderbolt connection to the display.