Yea, the bottom two are SSD drives
So, im not sure what drive comes in the PS4...im guessing a 500Ggig. So, if it was me, I would put a 240Gig SSD in the PS4, that will have the PS4 OS, and some storage, and then you use the 500Gig with the enclosure for your other games.
OWC is great about giving out that enclosure.
On all my Macbook pro's, i have always purchased the DataDoubler from OWC. That lets me take out the DVD Rom and put a Hard Drive in its place. Then they send you the free DVD Rom (Slot opening) enclosure so i can make my internal DVD Burning an External DVD Burning.