The access time is an important factor, which I've saved for last. This aspect can be split into two parts: the seek performance (including head positioning) and the access performance. Of the two, the seek procedure takes more time, as it positions the read/write heads over the corresponding cylinder/track. Then the drive has to wait with the initiation of the read or write procedure, until the disk has rotated so that the requested sector is directly below the read/write heads. Obviously, the delay time depends on the rotation speed, which is the shorter the faster the disk the rotates. This is why the Cheetah X15 has the world's shortest access times.
|Seagate Cheetah X15, ST318451 LC|
|Number of Discs||5|
|Average Seek Time||3.9 ms|
|Rotation Speed||15,000 rpm|
|Buffer Size||4 MB|