7970 and 6990 on same Mobo

[spartan442]

Has anyone had any success running a 7970 and 6990 on the same motherboard? I have two 7970s and two 6990. I would like to combine them onto one board instead of having two separate mining machines. I wanted to know if anyone has done this successfully before I start this project so I know what is involved, especially dealing with driver issues.

[lueo]

I have a machine with these cards:

6970 *1
6990 *1
7970 *1

Running with 11.12 with SDK 2.6 installed on Windows 7. (Have tried 12.1 but it failed to recognize all cards)

Average power usage is about 950 Watts.