Having said there are no exterior changes to the MacBook Pro, we should qualify that. Looking closely along the left edge, a difference between this and the previous MacBook Pro is visible - what looks like a mini-DisplayPort now has a small lightning bolt logo next to it, because it's no longer just a DisplayPort, but rather a new type of connector, and a major addition to this MacBook Pro - Thunderbolt.
For those not already aware, Thunderbolt is Intel's next generation high-speed interface, providing transfer speeds of up to 10Gb/s bi-directionally in its current copper-based implementation (later updates will add fibre optics to the mix). At a briefing at Apple's London offices, we saw an impressive demonstration using a pre-production external storage device, which hosed a RAID-0 array of disks (necessary as no hard drive can keep up with Thunderbolt's transfer speeds).
Using Final Cut on a new MacBook Pro, the bandwidth afforded by Thunderbolt enabled the playback of not one, but four simultaneous 150MB/s uncompressed high definition videos. We also saw file transfer speeds in the region of 800MB/s with the storage device proving the limiting factor to the data rate, not the interface. Impressive enough, but the setup also included an Apple Cinema Display daisy-chained off the storage device.
Apple supports up to six daisy-chained devices, of which only one can be a Display currently (Apple suggested this might change in the future, but wouldn't confirm that it would). What's really impressive, though, is that while electrical Thunderbolt cables have a maximum three meter length; integration of Light Peek means that with a fibre cable, Thunderbolt devices can be much farther apart. So if you're thinking of wiring up your house with CAT-5, you might want to think about adding Thunderbolt wiring to the mix, too.
The kicker, though, is that despite Intel's press release mentioning a number of companies which are committed to releasing Thunderbolt-interfacing products in the coming months, there's no use for it at the moment. That is, other than as a mini-DisplayPort, obviously; or a VGA, HDMI or DVI port via an adaptor. And it's not as if we can blame Apple for being ahead of the curve here.
From the short time we've had to play with the new MacBook Pros we have to admit we're suitably impressed. We'll have to reserve a full judgement on Thunderbolt until retail (not just prototype) products are available, and we'll be taking a proper look at a system in the next couple of weeks. But we'll go so far as to say that if you've been holding off buying a last generation system to see what the new MacBook Pros would offer, you should be logging onto Apple.com about now; go on, what are you waiting for?