Can anyone confirm me that even if the Bus speed is 8x or 4x, the render speed will be the same as having all 3 of them on 16x ?

Hey guys, I owe : Nvidia GTX 570 , Nvidia GTX 690 and NVidia GTX 670,

Cam Octorender Support al 3 of them and actually use them at all for best performance ?

Also, I do have this Available Mother Boards : Asus PX9X79 , 2X Gygabyte Z77x-UP4 TH , basically 3 computers. I have no idea how to arrange ...