Western Digital on Thursday revealed that its new My Book Thunderbolt Duo, a two-drive desktop RAID array equipped with Thunderbolt connectivity, is now available for purchase for $600 (4TB capacity) and $700 (6TB capacity).
WD's first Thunderbolt drive made its debut in January at the Macworld | iWorld show, but at the time, the company did not have details on capacity and pricing. The My Book Thunderbolt Duo looks very much like the drives demoed at the show, with a large silver case and a contrasting black grill. (WD no longer uses grills patterned with messages in Morse code.)
The My Book Thunderbolt Duo has two Thunderbolt ports, which gives you more flexibility when creating a Thunderbolt daisy chain--the types of devices, and placement of those devices in a chain, can affect performance. However, like other companies offering Thunderbolt devices, WD doesn't include a Thunderbolt cable. The cable has a retail price of $49 (Apple is the currently the only provider), and companies are not including the cable in order to keep prices down. The My Book Thunderbolt Duo does not have FireWire, USB, or eSATA connectors.
The My Book Thunderbolt Duo houses a pair of drives than can be configured as a RAID 0, RAID 1, or as a JBOD. The drive comes pre-formatted for the Mac using HFS + Journaled, so it's compatible with Time Machine right out of the box.
When compared to WD's non-Thunderbolt My Book Studio Edition II desktop hard drive, the Thunderbolt drive comes at a premium--it's $200 more in either 4TB or 6TB capacities. The My Book Studio Edition II, which has FireWire 800, eSATA, and USB 2.0, also includes FireWire 800, FireWire 800 to 400, and USB cables (no eSATA cable).
However, the premium buys performance that's a big improvement over FireWire 800 and USB 2.0. According to the specification, Thunderbolt is capable of data throughput of 10 Gbps, while FireWire offers 800 Mbps performance and USB 2.0 offers 480 Mbps speed. Macworld Labs has found that the boost Thunderbolt provides over FireWire and USB 2.0 is dramatic. In a January press release to announce the demonstration of the My Book Thunderbolt Duo at Macworld | iWorld, WD said that, "HD media creators will be able to transfer a standard size full-length HD movie in less than 30 seconds, or backup an entire year of continuous music (approx. 8,600 hours of music) in roughly 10 minutes."