Western Digital Caviar Green, 640GB: WD6400AACS
Released in 2008, Western Digital’s Green series is dramatically different from the others on one point: it has the mysterious word IntelliPower written in its specs against the spindle rotation speed entry. These HDDs had been supposed to vary the speed by lowering it from 7200rpm under load to 5400rpm in idle mode to save power but so far every test suggests that they just have a spindle rotation speed of 5400rpm without any variations. Besides, this series features economical electronics as we will discuss in an appropriate section. Can such products have any market success? Yes. If you are assembling a NAS or want to install a disk into an external storage device, you don’t need maximum performance whereas low power consumption, low temperature and reduced noise are most welcome. Samsung offers a similar series called EcoGreen, but Western Digital’s Green drives are more widespread as yet.
Western Digital Caviar Blue, 640GB: WD6400AAKS
The HDDs of the Western Digital Caviar Blue series were made by simple renaming. They had used to be called Caviar SE16. One of the early drives, produced before the series was renamed, is shown in the photo above. Later models got a different label that is designed to resemble the new series but is blue, of course. The label is the only change, though. The contents of the HDD case are the same. By the way, this model was the world’s first 640GB drive to begin selling in shops.
Western Digital Caviar Black, 640GB: WD6401AALS
Yet another drive from Western Digital, this one belongs to the high-performance Caviar Black series. Every disk of this series boasts 32 megabytes of cache memory and the Dual Processor feature. The point of the latter is explained rather vaguely at the company’s website – “Twice the processing power to maximize performance.” So, we don’t know if the HDD just has faster electronics or is really equipped with two independent processing cores. Anyway, we can expect more from the Black than from the Blue series.