The manufacturer is careful in not directly citing spindle speed, instead nominally positioning the Caviar GP as a "7200 RPM-class" drive. Under its "IntelliPower" moniker, WD claims a "A fine-tuned balance of spin speed, transfer rate and cache size designed to deliver both significant power savings and solid performance." Some folks have misinterpreted some admittedly vague specs on WD's website. Under "Rotational Speed," the manufacturer cites "IntelliPower (5400 to 7200 RPM)." This does not mean the drive dynamically changes its spindle speed during operation... indeed, such a feature would entail considerable mechanical engineering and would in many ways defeat the point -- rapidly accelerating and decelerating the spindle's speed would increase rather than decrease net power draw. Rather, the IntelliPower term indicates that the GP family as a whole does not have a set spindle speed (nor a set buffer size, for that matter). Different capacity points may feature differing spin speeds and buffer sizes. For those that must know, WD admits "sub-6000 RPM operation" for the 1-TB Caviar GP (more on this on the following page).