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.
There are almost no differences between the HDDs in terms of startup power consumption. None of them meets the USB 2.0 specification if installed into an external enclosure. Each HDD will have to be powered by two USB 2.0 ports. But if we take the new USB 3.0 standard, only two HDDs, the Samsung M7E and the Hitachi 7K500, will not be satisfied with its power capabilities.
By the way, you can install a jumper into the Western Digital drives that increases the time the HDD takes to spin its platters up, but lowers the startup power requirements. We checked this out with the 750GB model and found that its peak power consumption had lowered from 0.86 to 0.75 amperes. This can hardly be called a decisive improvement, though.
All the HDDs, with the exception of the Seagate 7200.4, fit within a 1-watt limit when idle. Three models can be singled out: the 750GB BPVT model from Western Digital, the Seagate 5400 and the Hitachi 5K500.B. As for the impressive result of the first of these HDDs, our ears tell us that it just shuts the motor down if there is no disk access for a few seconds. The power consumption you see in the diagram is what its electronics consumes, waiting for a disk request.
It is the new BPVT series drives from Western Digital and the Seagate 5400 that prove to be the most economical at random operations. The two 7200RPM models require a lot of power at random reading whereas the Hitachi 7K500, Seagate 5400.6 and the 500GB BEVT from WD have the highest power requirements at random writing. As for the possibility of using these HDDs in external enclosures, they can all be powered by a single USB port, except for the 7200RPM models.
The HDDs don’t differ much at sequential operations, the old Hitachi 5K500.B and the Samsung M7 being but slightly better than the rest of the drives. We’ve got only one loser in this test: the Seagate 7200.4 proves to require quite a lot of power at sequential writing, exceeding the 2.5-watt mark.