Western Digital's Caviar GP (Green Power) drive is a cut above the competition as far as power consumption is concerned. It takes advantage of an improved seek method for data, as well as a constant spin speed, to deliver the lowest power consumption in its class.

We ran the drive in a PC with a 650W Seasonic SS-650HT power supply and used a digital multimeter to record its maximum power consumption at various operational stages. In an idle state, the Caviar GP used only 3.66W of power, which is almost half as much as what Seagate's new 1TB Barracuda 7200.11 consumed. When writing and reading data, it used 8.24W and 7.7W, respectively, and this also compares favourably against the Seagate (10.62W when writing and 9.56W when reading).

Perpendicular recording technology has been used in the Caviar GP, which employs a four-platter design to facilitate its 1TB storage capacity. Each platter can hold 250GB of data, which is the same density as Seagate's 1TB Barracuda. The low number of platters and increased density also contribute to the lower overall power consumption of the drive, as less power is needed to drive the motor and less heads need to be moved when reading and writing data.

The most significant power saving appears to have been made from the reduced spin speed of the drive. During our measurement of the 12V power feed, which is used to drive the motor, the Caviar GP consumed a maximum of 3.24W. This is half the amount of power used by the Seagate Barracuda 7200.11, which spins at 7200rpm. Western Digital hasn't specified the spin speed of the 1TB Caviar GP, but says that the spin speeds for GP drives can vary from 5400rpm to 7200rpm depending on the model.

A lower spin speed can have an adverse effect on performance, as the platters take longer to swing data around to the waiting heads, but the benefits can be lower vibration and reduced heat. In both instances, the Caviar GP was stellar. It ran without noticeable vibration or noise, for the most part, and didn't get overly hot. At times, some soft clicks could be heard from the drive, which were due to the heads parking themselves when the drive was in an idle state.

The Caviar GP's performance was also relatively swift. We were expecting it to be sluggish, but it actually scored highly in our tests. It wrote data at a rate of 67.32MBps, which is only 5MBps slower than what Hitachi's 1TB and Seagate's 1TB drives did in the same test. It read data at a rate of 67.76MBps, which is just over 1MB slower than what the Hitachi and Seagate drives achieved. Meanwhile, in our file transfer test, where we copy data from one location on the drive to another, the Caviar GP transferred data at a rate of 26.89MBps. This isn't a stellar result; it was slower than Hitachi's 1TB drive, but faster than Seagate's 1TB Barracuda.

When it comes to value for money, the Caviar GP, with a formatted capacity of 931GB and a retail price of $559, has a cost per gigabyte of 64 cents, which is slightly high.