Power efficiency is increasingly becoming a significant factor in environmentally conscious customers when making purchase and deployment decisions, and hard drive manufacturers have taken note of that. Back in July, Western Digital unveiled its GreenPower series hard drives, claiming reduced power consumption of as much as 40% compared to other models. Now, Hitachi has announced its own line of eco-friendly hard drives which, according to the company, consume far less power than anything else on the market while maintaining the performance users expect from a high-end drive.

The DeskstarP7K500 drives have up to 250GB per platter, and are available in 250GB, 320GB, 400GB, and 500GB capacities, in 300MB/s Serial ATA or 133MB/s ATA flavors, and with cache sizes of either 8MB or 16MB. Unlike Western Digital, which varies the rpm of its GreenPower drive to cut down on power consumption, the Hitachi drives maintain 7200rpm across the board.

The company says its P7K500 drives have idle power utilization of 3.6W for the 250GB model and 4.8W for the others. Under full load, the 250GB will require 6.4W while the higher capacity models will require 8.2W of power. By comparison, WD’s GreenPower drives are rated for 4W when idle and 7.5W when seeking.

While that 3-4 watt difference a green hard drive makes might not be a lot on the desktop, it could represent significant energy costs savings for large data centers with thousands of such drives. The new P7K500 drives are expected to start shipping in volume before the end of the year, with no price premium as compared to the current line of same-capacity drives.