A minimum idle power consumption of 3.1 W is a new record. WD’s WD5000AACS Caviar GP (500 GB) is the most energy-efficient drive, although it provided the lowest performance in this roundup. Hitachi’s 7,200 RPM spindle speed is a disadvantage, as the idle power is almost 50% higher! However, the Hitachi drive still is much more efficient than other 7,200 RPM drives, which consume 6+ W in idle.
Looking at maximum power consumption, Hitachi is even lower than the WD drives despite the higher spindle speed. If you remember the slow access times then you already know how this was achieved. If you want an efficient desktop drive, Hitachi offers the better performance per watt ratio, as the performance is clearly higher at similar power consumption results.
The drives do well when it comes to surface temperature. As expected, the WD drives, at less than 7,200 RPM, stay cooler than the 7,200 RPM Hitachi. Note that the WD VelociRaptor, which is on top at only 38°C surface temperature, is a 2.5” 10,000 RPM drive.