Road Testing the PowerBook Ti 667
Subject:   RPM: Wrong
Date:   2001-12-02 01:50:31
From:   rwagoner
Response to: RPM: Wrong

It sounds as if you are only thinking of data transfer rates at the extreme ends of the platters. But the 3.5 inch uses an area that includes all the area of the 2.5 inch drive; combined with the fact that 3.5 inch drives are generally larger in capacity than 2.5 inch drives (hence the density should be similar), you end up back at the point where the faster angular velocity equates to a faster data rate.

Additionally, the linear velocity at 3.5 inches is far greater than at 2.5 inches at the same angular velocity (RPM).So other than head movement, assuming similar densities (and I am in no way a hard drive expert so this assumption may be wrong), the 3.5 inch drive is again faster.