How exactly is a Caviar black faster than say, a Caviar Blue

im pretty sure the blacks have a integrated dual processor for better performance. the blacks also favor performance over noise and energy. the only wd black i have had was really loud. it worked fine just louder then any hdd i have ever owned. not sure if i just got a bad drive but it was annoying.

Sustained transfer rate is dependent on data density, so if two drives have the same capacity and RPM, but one has less heads, then it will be faster.