Group Test: Thunderbolt external drives
Hard disks using the superfast Thunderbolt interface are starting to appear – but do the performance benefits justify the price? We put four quite different drives to the test.
Thunderbolt ports have been appearing on Apple hardware for more than a year now, and they’re slowly starting to show up on high-end Ultrabooks and motherboards too. There’s been a lot of buzz surrounding this high-speed, multipurpose interface, but as yet few consumer peripherals have made use of it. Now, however, we’re starting to see Thunderbolt emerge as a connector for external hard disks.
The appeal of Thunderbolt for connecting drives is obvious: it offers a huge 10Gbits/sec of bandwidth. This doesn’t mean a Thunderbolt drive will transfer data at that rate, since hard disk technology simply isn’t capable of that sort of performance. But it means there’s headroom for the disk to perform at its maximum speed, whatever that may be. This is a big advantage over older USB 2 drives, in which the 480Mbits/sec connection speed keeps transfer rates low. Even USB 3 drives, with 5Gbits/sec of bandwidth, could bottleneck today’s fastest SSDs – especially if they’re combined into a striped RAID array.
Another benefit of Thunderbolt is support for daisy-chaining, allowing you to string together drives neatly, rather than each one requiring its own port on your PC. You can even attach a monitor to the chain, since Thunderbolt carries DisplayPort data alongside other protocols. Monitors consume a lot of bandwidth, though, so be warned that this may reduce the performance of other peripherals attached to the same host port.
There are downsides to Thunderbolt, however, and the first is the price. Thunderbolt is currently a small market of high-performance parts, and the prices reflect that. Even a cable will currently set you back around $50.
The second issue to be aware of is power consumption. Thunderbolt is a more electrically complex system than USB, and drives connected via Thunderbolt draw more power than USB 3 ones. In our tests, we found USB 3 disks typically added around 4W to total system load when spinning idle, while Thunderbolt disks added around 10W. If you’re powering a portable drive from a laptop, that difference could have a significant impact on battery life.
To test our Thunderbolt drives, we used a Windows 7 test rig comprising a Gigabyte Z77X-UP5 TH motherboard, an Intel Core i3-2100 CPU and 4GB of RAM.
Clearly, Thunderbolt drives are fast – but they’re also expensive, and for everyday use there’s much to be said for sticking with USB 3 (especially considering that any PC with Thunderbolt is guaranteed to have multiple USB 3 ports). For professionals, however, who are willing to pay for top-speed storage, Thunderbolt is exciting – and as the market grows, prices will surely fall. We look forward to seeing what Thunderbolt brings in the coming months and years.
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