We can whizz data around inside our Macs at phenomenal speeds now. Thanks to solid-state flash storage and the latest PCIe-connected data buses in the most recent Apple Macs, we’re now starting to catch up with advances in processor technology.
Getting the data in and out of the computer though – that’s another challenge, and a task that Steve Jobs was said to be keen to both accelerate and simplify, leading to the development of technology that is now known as Thunderbolt.
Apple may have inspired Intel to develop Thunderbolt, but neither company has done a great deal with the technology since. Besides the fitting of these promising high-speed data ports to practically every Macintosh (and one desktop monitor) over the last three years, Apple has relied upon other companies to make useful things to plug into them.
Most of Thunderbolt devices currently on the market are storage drives, and available in all manner of shapes and sizes – both physical size and in data capacity. We rounded up eight of the most interesting and potentially invaluable models to gauge the current state of the Thunderbolt art. That’s four mobile drives that can power from a MacBook port, and four desktop-sized units that need external mains power.
One thing Intel has revised since its first launch is the maximum single-device throughput, perhaps rising to the distant challenge from the USB camp that is promising faster speeds from USB 3.0. The revision is simple called Thunderbolt 2.
Thunderbolt 2: The Sequel
Thunderbolt 2 is a modest evolution of the original Thunderbolt spec. Where the initial version allowed two separate channels with nominal 10 Gb/s speed – but full duplex, meaning data can flow at that speed in both directions simultaneously – the new Thunderbolt 2 has only one duplex channel, but with twice the nominal bandwidth, now standing at 20 Gb/s.
So the overall speed hasn’t changed, just the way the channels are configured: now we have something akin to line bonding, putting two slower channels together to create one faster channel.
Thunderbolt 1 could allow data to transfer in one direction at a maximum theoretical speed of 1250 MB/s. And in real use, we have seen speeds up to 869 MB/s; in fact, that was the best-case sequential read speed from the original Promise Pegasus R6, the first ever Thunderbolt device launched after Apple’s MacBooks of February 2011.
Thunderbolt 2 should allow twice this speed – 2500 MB/s at the physical layer anyway, with actual user data throughput somewhere below this. In the following pages we have two storage devices that incorporate Thunderbolt 2; and both make use of the wider pipe to allow transfer speeds previously unavailable to the Mk 1 conduit.
Thunderbolt devices of either generation can happily co-exist on the same cable, although the new TB 2 device will be restricted to TB 1-like 10 Gb/s speeds.
With drives varying in size from a few centimeters across and weighing just a few grams, the heavy multi-disk spinning RAID arrays that will deliver vast pools of data at high speed, there’s certainly plenty of diversity in the Thunderbolt pool. Be aware though, that best performance can only be found from mains-powered storage drives, as bus-powered drives are currently starved of enough power to allow speed enough to satisfy even SATA-based SSDs.