Dell T3500: Gaming and SSD question.

Hello everyone! I have some questions, I hope someone can help me. I found a Dell T3500 at a good price, it has the Xeon W3580, 12GB of RAM and 1TB HDD, that seems pretty good to add to my GTX 950 and play some games I cant right now due to my good old Core 2 Quad I have right now, it cant keep up with some more demanding games. I already checked some videos on Youtube and it does handle the latest game with easy with a GPU.

The problem I saw is that I see this Dell only has Sata 2.0. Is that correct? Does it means the HDD is slower? How much? My current computer has Sata 3.0, it also uses a Micron C400 SSD, which makes it lighting fast. Could I use my SSD on the Dell? Or will there be any issues? I really want to use my SSD for some games and the O.S, the HDD will be for much bigger games and the rest of programs and data.

Hope somebody can share me some light on this issue.

Thanks everyone!