I have recently purchased an ASUS 6950 2gig graphics card and I've been trying to get this thing up and running. The card has the space for a 6 pin and 8 pin connection, but the asus website claims that 2x 6 pin power connections are enough to get this card running. Up to this point I've been trying to use the 2x 6 pin option as I do not have an 8 pin connection from my PSU. One of my 6 pins has an additional 2 pins hanging off the side, but the cables are both black and I've been told by a friend that they could kill the card if plugged in as well.
Some more information that could be useful is that upon start up, a red light on the back of the card appears and the fans function fine. Also on start up my pc makes 1 long beep and 3 short beeps.
My PSU is a 700 watt OCZ gameXstream which should be able to handle the 6950 fairly easily. Furthermore, we plugged the card into my friend's PC and it functioned fine. He has a 1000 watt PSU with the 6 pin and 8 pin cables - however, my 700 watt and 2x 6 pins should be fine according to ASUS.
I also haven't installed any ASUS drivers yet, but I would imagine the card would still show some performance.