I have a Gigabyte Z77-D3H, which has a PCIE 3.0 @ x16 and PCIE 2.0 @ x4. I have currently a GTX 660 Ti, if I get another one will I be able to run SLI? Will it limit the performance much? Also, I hope it's ok to ask this, but how does this work? Does it make it run @ 8x 8x?