The MacBook Air has always been a sweet little machine, but with the noteworthy constraint that there is no means of fast input/output — USB 2.0 is as fast as it gets on most of them, and that’s not even as fast (in actual real usage) as FireWire 400, much less FireWire 800, much less Gigabit Ethernet.
Fortunately, the very latest MacBooks (all flavors) have USB 3.0, which is, based on my experience, really quite fast. Which is great, but what if you have one that still has USB 2.0, or you don’t have USB 3.0 devices? What about FireWire devices, which can’t even be attached at all?
Fortunately, Apple has finally released two Thunderbolt adapters: one for Gigabit Ethernet, and one FireWire 800. The good news is that they’re available to any MacBook Air with a Core i3/i5/i7 CPU (not Core 2 Duo; those models doesn’t have Thunderbolt, only Mini DisplayPort). And they’re reasonably priced, at $29 each.
The bad news is that with only one Thunderbolt port on the Air, you can’t use both, and you can’t use any other Mini DisplayPort device such as an external display, unless it’s the Apple Thunderbolt display, which provides another Thunderbolt port, as well as the aforementioned ports. (With the Retina, this is less of a problem, as you get two Thunderbolt ports.) Still, this solves a pretty big throughput and device connection problem for MacBook Air users who didn’t want to shell out $1,000 on a display.
One caveat, though: I recently ran Migration Assistant using the Thunderbolt Ethernet adapter to an older MacBook, and it was insanely slow. Something had to be wrong, and I didn’t have time to find out what it was. I popped the drive out of of the older Macbook, put it in a USB 3.0 enclosure, and it was done in less than two hours.
Thunderbolt lets you have FireWire and Gigabit Ethernet for your MacBook Air
What’s the Difference between Thunderbolt and USB on the Mac?