There has been some confusion about whether Western Digital's IntelliPower technology varies a drive's rotation speed or not. Well, it doesn't.
A WD spokesperson said that IntelliPower does not vary a drive's spin speed while it is in use. The drives have fixed spin speeds and these may vary with individual drive capacity points within a particular drive model.
But the 1 and 2TB AV-GP drives both have a 5400rpm rotation speed.
IntelliPower is the marketing name for a particular choice of spin speed, caching algorithms, and transfer rates that WD uses to indicate a drive has a low power draw combined with good performance characteristics. The inference is that pure rpm numbers alone don't provide an adequate picture of a drive's performance.
However, for technology aficionados, spin speed is an essential element in understanding a hard drive's overall performance characteristics and being able to compare and contrast it to other drives from the same and from different manufacturers. ®