Energy-Efficient Hard Drives Compared

These hard drives are not meant to break new records in performance, but they might be able to break records when it comes to storage capacity per watt of power used. Both Hitachi Global Storage Technologies (HGST) and Western Digital have now released disk drives that cater to the power-conscious audience. The Hitachi Deskstar P7K500 and the WD GreenPower series reduce power consumption by up to 40% compared to conventional hard drives. We wanted to know what the impact on performance was of these design changes, which must not be significant for these products to be accepted in the market.

Looking at power requirements of 50 to 120 W for TFT displays, 20 to 120 W for processors, 25 to 200 W for discrete graphics solutions, up to 50 W for high-end motherboards and another 10 to 20% of the component power requirements due to losses in the power supply, a discussion of hard drive power requirements might seems of little interest. After all, the typical power consumption of a desktop hard drive lies anywhere between 5 and 15 W, depending on the model, spindle speed and platter count. In fact, choosing one drive or another does seem to have little impact on the power consumption of a desktop PC.

Yet the hard drive does have a measurable impact on power requirement in applications outside of a typical desktop PC environment: think of data centers, where thousands of hard drives are required to satisfy enormous storage requirements. And while any device not only consumes a certain amount of power when it operates, it is also produces heat that must be removed via air conditioning solutions. As a matter of fact, the effort and cost of deploying large-scale, fail-safe air conditioning solutions may be more significant than the direct cost and impact of device power consumption.

Other applications for low-power hard drives are consumer electronics devices such as personal video recorders (PVRs), set-top boxes with integrated storage, and all sorts of backup devices such as external hard drives and RAID-based solutions for near-line storage. These need to be as cool, quiet and as easy to maintain as possible, and they don’t even require great performance. Most of the hard drives that are integrated into consumer electronics products are actually still based on UltraATA interfaces rather than on Serial ATA.

Hitachi and Western Digital both have products to cater to these markets: the Hitachi Deskstar P7K500, where the P stands for “power”, and the Western Digital GreenPower series, which includes a number of power optimizations that can be found across various WD product lines.