The question is: Does performance suffer as a result? I tested two 2TB SATA internal drives to find out.

Slideshow: 5 Tools to Prevent Energy Waste in the Data Center

How we tested

In order to test the drives, I installed them into a Dell Dimension desktop running Windows XP SP3 and connected them to Promise Technology's SATA300 TX4302 card, which enables older systems to benefit from SATA technology using a standard PCI slot.

I tested the drives with HD Tach 3.0 from Simpli Software using its grueling Long Bench test, which uses 32KB blocks for reads and writes across the entire drive. I also used version 2.55 of the HD Tune benchmark test (since it's always a good idea to try more than one benchmark when you can).

Seagate Barracuda LP

Seagate's new $299 Barracuda LP SATA 3Gb/s 2TB drive ("LP" meaning low power) spins at 5900 rpm (most lower-power drives spin at 5400 rpm).

According to Seagate, the drive uses as much as 50% less electricity than standard desktop hard drives and up to 25% less than competitors' "green" drives. It uses 6.8 watts when in operation, which is 15% less than the 1.5TB Seagate Barracuda drive I tested in October 2008. It uses just 5.5 watts when in idle mode.

Among its other environmentally friendly properties: Seagate claims that 70% or more of the materials used in the drive are recyclable and that the drive meets the RoHS (restriction of hazardous substances) environmental standards. According to Seagate, the drive is also well suited to newer low-power PCs, networking appliances and personal attached storage devices.

Seagate uses the slogan "The new low-power drive that won't slow you down" on its data sheet. However, its performance certainly isn't as good as the current slate of full-power traditional drives; you'll pay a 10% penalty for eco-friendliness. On the HD Tach test, the drive had a burst speed of 113.8Mbit/sec. and an average read speed of 92.4Mbit/sec. Compared to my results when I tested last year's 1.5TB Barracuda, burst speed is 13.5% slower and read speed is 10% slower.

HD Tune reported an average transfer rate of 74.3Mbit/sec. (a 20% decline over last year's Barracuda), a burst rate of 77.9Mbit/sec. (16.5% slower), and an average access time of 12.2 milliseconds (an 8.9% drop).