Results: Power Draw And Efficiency
There's nothing particularly exciting to report from our power consumption numbers. If we look at the raw results on their own, we see a fairly normal range.
The most power-friendly drives are predominantly the 5400 RPM disks. Naturally, a slower motor draws uses less energy. The Travelstar 7K1000 HTS721010A9E630 does not surprise us, winding up in the middle of the field, with one exception. During HD video playback under VLC, the Travelstar 7K1000 draws a mere 0.8 W, which is the lowest reading among all drives.
When we calculate efficiency, we put each drive's power consumption in relation to performance parameters like IOPS or streaming write throughput. The clear winner in the IOPS per watt discipline is Western Digital's Scorpio Blue WD10JPVT. HGST's newer Travelstar 7K1000 HTS721010A9E630 doesn't fare particularly badly, but it's also not outstanding. The picture changes when we look at streaming write efficiency. In that metric, the drive takes a first-place crown. No other disk achieves higher write performance per watt.