Hitachi replaced its DeskStar line with these P7K500 energy-savers, rolling out in capacities from 250GB to 500GB.

The drives run at 7200RPM, they’re up to 59% more power efficient, with the 250GB drive sipping just 3.6 watts when idle (the 320GB and higher drives use 4.8 watts)

Energy-saving features:

• Switching regulators have replaced linear regulators for more effective voltage conversion inside the drive.
• The Travelstar system-on-chip design has a new, power-efficient profile.
• In the drive’s new “unload idle” mode, the drive heads are actually unloaded to the ramp and the drive’s servo shuts down (although the platters still chug along at 7,200 RPM), which saves a bit of juice.
• In the drive’s “low RPM idle” mode, the platters themselves spin down to 4,400 RPM.

The models schedule to hit stores later this quarter.