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.
Seagate’s HDDs need the highest start-up current (over 2A on the 12V alone) irrespective of the speed the drive’s platters are going to rotate at. They have the lowest 5V consumption, but every other HDD is quite modest in this respect, too. None of them needs more than 1 ampere from this power rail. Western Digital’s products are the most economical overall.
When there is no load, the Hitachi looks poor compared to the others. It has one platter more than its opponents, yet even its power draw fits into 8 watts. Western Digital’s products are just perfect, their electronics consuming only half the power their predecessors needed. The Barracuda XT’s electronics consumes quite a lot, which must be a tradeoff for SATA 600.
The Western Digital drives’ electronics is somewhat hungrier in comparison with the other HDDs at random reading, but the 12V line is more important here. The Seagate Barracuda XT, having suffered from its slow heads throughout this entire test session, shows its best now. Its overall power consumption is similar to the HDDs with lower spindle rotation speed. An inexplicable fact can be observed with Western Digital’s HDDs: the RE4, being somewhat faster through our tests, proves to need less power than the Caviar Black. The Hitachi 7K2000 is poor: besides five platters, it has to move a block of ten rather than eight (as in the other HDDs) heads. Of course, it is more economical than the previous 5-platter product (which had a power consumption of 16 watts) but not as good as its opponents.
We see a similar picture at random writing: the Seagate XT is competing with the power-efficient HDDs among which the Barracuda LP, thanks to its economical electronics, outperforms the WD Caviar Green, which needs less power from the 12V line. Yes, Western Digital’s HDDs need more power for their electronics with high-performance firmware than the 1-terabyte RE3 and Caviar Black models. Perhaps this is the contribution of the additional piezoelectric heads actuator. Anyway, the Hitachi 7K2000 still remains the most voracious drive as its mechanics consumes too much.
The standings are almost the same at sequential reading and writing: the power-efficient WD Caviar Green and Seagate Barracuda LP are more economical than the 7200rpm products. Among the latter, the Seagate and Hitachi are competing for top place whereas Western Digital’s HDDs still need a lot of power for their high-performance electronics. Interestingly, the RE4 needs less power from the 12V line than the Caviar Black.