You can refer to our article called Hard Disk Drive Power Consumption Measurements: X-bit’s Methodology in Depth for details on this test. We will just list the specific modes we measure the power consumption in:
- Start (the current the drive consumes when starting up)
- Idle (the drive is not accessed at all, but it is turned on and ready to work)
- Random Read and Write
- Sequential Read and Write
Let’s check out each mode one by one.
The WD Black and the WD Blue A7 need the largest amount of power to start up, and their results are again suspiciously similar. The WD Green with 32MB cache and the Samsung F3 boast the lowest power consumption here. We can note a couple of general trends: the newer models from every maker are more economical. The other trend is that Western Digital’s products consume more power from the 5V line than the other HDDs.
It is the power-efficient products that feature the lowest power consumption when idle. These are the Seagate LP and the Samsung F2. Third place is shared by the power-efficient WD Green with 32MB cache (note that its dual-platter cousin with 16MB cache needs more power) and the Hitachi 7K1000.C. Finally, we’ve found a good trait in the Hitachi drive.
The single-platter 7200RPM models are more economical than their dual-platter counterparts, the best of them requiring less than 5 watts. The WD Caviar Black is now alone in last place. As opposed to the similar drive from the Caviar Blue series, it probably does not switch into sleep mode.
The heads are moving a lot at random reading but the cache memory is idle. As a result, most of the HDDs consume about the same amount of power from the 5V line, excepting the WD Green with 16MB cache which seems to belong to the first generation of the Green series that has very voracious electronics. The HDDs are also similar in terms of 12V consumption, the power-efficient products intermingling with the 7200RPM ones. The best power-efficient drive, Seagate LP, is a mere half a watt better than the WD Blue V1.
The Seagate 7200.11 and WD Blue A7 are on the losing side. We don’t know why the latter needs 50% more power from the 12V line than the WD Black which delivers similar performance under this load.
The electronics, powered by the 5V line, contributes more to the overall power consumption at random writing. The Seagate LP and Samsung F2 are in the lead, third place going to the Samsung F3 which has moderate consumption on both lines.
The WD Blue A7 is surprisingly the most uneconomical HDD here.
The power-efficient drives from Seagate and Samsung are best at sequential operations, too. The WD Blue A7 is last, again. The Hitachi 7K1000.C is quite amazing at reading: it seems not to use its electronics at all! At writing, the Seagate 7200.12 becomes unexpectedly third.
Overall, we can note that the HDDs all keep at about 7 watts under any load. This number can be considered the typical power consumption of modern 500-gigabyte hard disk drives.
The very small advantage of the power-efficient models is somewhat expected for us. The modern motors seem to consume very little power when rotating a single platter, so there are but small power consumption benefits from reducing the rotation speed.