Data transfer rate is the measurement that encompasses both the internal transfer speed of a hard drive (movement of data from the disk surface to the disk controller in the drive) and external transfer speed (data movement between the disk controller and the host operating system). The data transfer rate is typically benchmarked and recorded as the slowest of these two numbers in order to represent the real world conditions under which the device transfers data.
Modern solid-state drives have a radically faster data transfer rate thanks to their completely electronic data transfer cycle which is not slowed down by the movement of physical parts. Magnetic hard drives are typically bottled-necked not by the host hardware, but by the limits of the mechanical components within the drive. Solid-state drives, on the other hand, typically max out the transfer capacity of the drive-to-host interface.
- By Jason Fitzpatrick on 10/24/13