Western digital has released a range of hard drives purporting to save up to 40 percent in power consumption over comparable drives. We found the drives not only lived up to promised efficiency, but also were competitively priced.

Design and features
GreenPower hard drives from Western Digital come in 500GB, 750GB and 1TB sizes in both the RE2 and Caviar ranges of drives. Western Digital supplied us with the 1TB model for this review. The interface is a 3Gbps SATA type with a 16MB buffer.

Western Digital uses a variety of methods to improve the energy efficiency of its product, such as optimising spin speeds to suit the amount of data being read or written.

There is no point spinning up to maximum speed to write a few bytes — it is inefficient in terms of both power and time. Naturally the drive goes to idle mode when not needed and the read/write electronics are disengaged to save further energy. Clever caching provides additional savings where Western Digital claims that these drives can save US$10 each per year using current US energy prices. Reducing the time spent spinning-up the drives also means less annoying noise.

The RE2 drives feature additional RAFF and active Power Management technologies to improve drive reliability and energy efficiency. Western Digital claims a Mean Time Before Failure of 1.2 million hours for RE2-GP Green drives.

Verdict
With the RE2 drives' extra reliability and efficiency there is no real sacrifice made in terms of speed. We detected only a very slight advantage in the Caviar drives, an additional one percent, which was not a statistically significant difference.

Speed tests were performed by timing copy processes of single large files (148MB) and a large directory containing thousands of files (total 7.45GB). Our single file copy test gave us performance scores of around 84MBps — just as the specifications claim.

We compared the power consumption of Western Digital's drives to a 250GB Samsung HD250HJ. Being a smaller drive you would hope that Samsung has lower power consumption than the 1TB GreenPower drives. During read/write operations we saw similar power usage, whereas on standby the Western Digital drives used 40 percent less on idle and 27 percent less compared to the Samsung.

Incidentally, Western Digital claim power usage of 7.4W during read and write — we measured approximately 7.1W. We also recorded a 25 percent reduction in power use when in idle compared to Western Digital's specifications.

Given our experimental power consumption figures and the fact that clever management allows the device to become idle more often, we would expect some great cost benefits arising from the use of these drives. In addition, they don't cost more to buy than other Terabyte SATA drives on the market, making them worthy of the Editors' Choice award.

These drives are supplied with an excellent five-year warranty (though this is from date of manufacture — not purchase), which provides one with confidence in data security. As does the incredible 1.2 million-hour Mean Time Before Failure!