Energy-Saving Hard Drives


The Hitachi Deskstar P7K500 and the Western Digital Caviar GP both live up to expectations, as they both reduce average idle power consumption by up to 50% and maximum power requirements by 20% to 30%. This difference isn’t really important for home users, as the power savings of 3-5 W compared to regular 3.5” hard drives are negligible. However, consumer electronics devices, which you want to be quiet and cool, clearly benefit from such a drive. Large server deployments with hundreds or even thousands of hard drives will also show a noticeable impact due to reduced power requirements both for running the devices and cooling solutions. Also, users looking for a reasonable upgrade may consider such a drive as long as there is no price difference compared to other models. Hitachi also offers an upgrade option with the P7K500, as it is also available with the UltraATA interface.

Thanks to having kept the 7,200 RPM spindle speed, Hitachi offers superior transfer rates across all benchmarks, and overall decent desktop performance. However, access times and I/O performance cannot compete with other 7,200 RPM drives, as Hitachi slowed down actuator movements in order to save energy. This is why the P7K500 requires even less maximum power than the 750 GB and 1000 GB WD Caviar GP drives.

WD reduced the spindle speed from 7,200 RPM to somewhere in between this speed and 5,400 RPM, which results in a new record in power consumption: 3.1 W idle power for the 500 GB model and 3.6 W for the 750 GB Caviar GP are excellent results. Should you be looking for one or even several efficient storage hard drives, the Caviar GPs will be the best choice. Hitachi, however, is the better choice if you also want to use the energy-efficient hard drive to hold your operating system.

Comparison Table

Manufacturer Hitachi Western Digital Western Digital Western Digital
Model Deskstar P7K500 Caviar GP Caviar GP Caviar GP
Model Number HDP725050GLA380 WD5000AACS WD7500AACS WD10EACS
Form Factor 3.5" 3.5" 3.5" 3.5"
Capacity 500 GB 500 GB 750 GB 1000 GB
Spindle Speed 7200 RPM > 5400 RPM > 5400 RPM > 5400 RPM
Other Capacities 250, 320, 400 GB 750, 1000 GB 500, 1000 GB 500, 750 GB
Platters 2 2 3 4
Cache 8 MB 16 MB 16 MB 16 MB
NCQ yes yes yes yes
Interface SATA/300 SATA/300 SATA/300 SATA/300
Warranty 3 years 3 years 3 years 3 years