I'm trying to do the same thing. However the cables provided for the video cards consist of two 6A and two 10A cables (at least they had that label on them). I need to get an extension cable for the white connector cables as well because they will not reach in their current state. I know the splitter cable takes those two 3-pin white connectors, but what cables go into the 8-pin splitter? the two 10A, the 10 and 6, or both 6?