PS4pro supports SATA 3.0

[vivster]

Radek said:

You can buy Samsung 850 Evo 500GB for around 150$ / € and many people do.
Might seem like a lot, but I'd buy one and install in my PS4, except it has SATA II so there's no point.

The speed difference from an SSD comes mostly from its random access speed and not sequential read. That means that even on SATA2 an SSD is unbelievably faster than any HDD. Unless the game is constantly loading huge files, there will not be a lot of diffrence in overall time savings between SATA 2 and 3. The difference to HDDs will always be huge though.