Hitachi's Global Storage Technologies division has rolled out its second-generation terabyte hard drive - the world's most energy efficient 7200rpm 1TB HDD, it claimed.

The 3.5in Deskstar 7K1000.B consumes 43 per cent less power than its predecessor, Hitachi said. That's in part because it uses three platters - each holding up to up to 375GB of data - rather than five, cutting the number of read/write heads from ten to six.

The 3Gb/s SATA drives also use power management techniques developed for mobile hard drives.

Hitachi said the drives provide on-board automatic data encryption based on the Advanced Encryption Standard (AES) - tough enough for the US government, apparently.

The Deskstar 7K1000.B and a version designed for 24x7 operation, the Deskstar E7K1000, go on sale later this month priced at $239 (£121/€152) and $279 (£141/€178), respectively.

Group Test Four 1TB HDDs