This is probably to have some decent ring fight with Western Digital’s Green series hard disk; Seagate is introducing a new range of eco-friendly internal HDDs called the Barracuda Green.  Coming in sizes up to 2TB, these new breed of energy efficient HDDs are equipped with a SATA 3.0 (up to 6.0 Gbps) interface, a 64MB of cache memory, a very odd 5,900RPM spindle speed and consume just 5.8W of power during normal operation and an average idle power of only 4.5W. This would be the perfect drive if you need your computer to run 24hours every day.

SOURCE via Seagate