So you plan to run your programs on the hard drive and your OS on an SSD. First off, Qing Dao is correct. SATA level is not a factor in the performance of today's mechanical dives. You'd almost be better off getting a 512GB SSD for your OS, programs and games. Then go with a 500GB mechanical drive for storage. The two downsides are one cost, and two, if your notebook only has room for one drive, then you'd need to remove your optical drive and use an optical to hard drive caddy.