| SATA 2 (3 GB/s) and SATA 3 (6GB/s) so be careful and keep them straight.|
If the system's available SATA port is '2' (3GB/s) then either SATA 2 or SATA 3 SSD will run at 3GB/s speed up to the ability if the drive (read/write speeds). On a system with an available SATA 3 port (6GB/s) a SATA 3 SSD will run at 6GB/s and a SATA 2 SSD will run at 3GB/s speed up to the ability of the particular SSD drive (read/write speeds).
I hope that this clears things up some for you.
You have to be a little bit crazy to keep you from going insane.