Why would you need to slow a SATA II hard drive?

Question

I was going over some of my older drives and found a Seagate SATA drive that had a jumper inserted for 1.5Gb/s mode. I pulled the jumper and low an behold, it is a SATA II drive.

Why would this be an option in the first place and why would Seagate have put this jumper in place from the factory?

Is there any need for a drive capable of fast SATA II speeds (well, faster than SATA I anyway) to be made to perform at SATA I performance levels?

Answer 1

Why would this be an option in the first place?

To prevent compatibility problems with older SATA controllers which only understood SATA 1.5 Gbit/sec.

why would Seagate have put this jumper in place from the factory?

Because it makes their drive 'more compatible' without slowing it down.
(1.5 gbit/sec is way faster than a spinning drive can read data).

Answer 2

It is necessary for the first generation SATA controllers found on old motherboards or controller cards; in short, for backward compatibility for older systems.