Should be quite fine. Each HD 6950 is a 200W TDP card that will draw 16.7A on the +12V rail at max. http://www.hwcompare.com/6215/radeon-hd-6950-2gb/
The 77W processor will max out at 6.4A on the +12V rail. Those are the heaviest loads most PCs have on the +12V rail. Your PSU has a 62A (744W) +12V rail, so I see no issue.
I'm just wondering if the PSU that you are planning to use has (2 sets) of 6 pin cables for the PCIe? I ask because I'm planning to do almost exactly what you are....crossfire (2) 6950's (only I've flashed them to 6970 an then overclocked them) but the set up requires (2) sets of 6 pin connectors.
I'm likely going to go with a 850w based on reading and recommendation others gave me so far here at Toms. Just have to find one with 2 sets of 6 pins on 12v rails.
Your right...it does have (4) 6 pin pcie connectors. I looked at the photos and you can see them.
Replying to your question Phippsy..."i only got 2 with mine think i got one that got packed wrong i had to use 6 pin fitting from another psu and a molex is this ok"
I'm not sure if that makes a difference or not as long as its carrying 12v. Hopefully someone here can clarify if the "correct/prefered" route is supposed to be 4 dedicated 6 pin PCIe connectors... or if they way you are looking to do it is alright as well.
Another member just pointed me to this good lin today..Its worth looking at: http://
As the chart OldtimeGamer linked to shows, even AMD's own specs show a 700W recommended for 2 x HD 6950. Thus the PO's 750W Corsair is sufficient. So, if the OP is missing his PSU's extra 6-pin connectors (and his PSU is indeed the one I linked to), using Molex to PCIe with the supplied adapters from the card(s) would be fine*. The PSU is a single rail unit so all +12V circuits are common, both PCIe and Molex.
*But be sure to use the SUPPLIED adapters. They will be wired in such a manner as to provide safe current carrying capacity to the 6-pin connector, and may require 2 Molex per 6-pin.
I was reading about different PSU wires here: http://
Under the section for 6 pin PCie AKA PEG cables, it says....
"If your power supply doesn't have a 6 pin PCI Express cable then you can use the adapter shown above on the right to convert two 4 pin peripheral cables into a PCI Express cable. If you use an adapter then be sure to plug the 4 pin peripheral connectors into separate cables coming from the power supply. If you plug them both into the same power supply cable then you are drawing all the power of the PCI Express connector through a single 18 gauge wire. You can usually get away with that but there's no reason to do it."
So as long as you makes sure you use (2) molex plugs and they are each on different cables... it seems you will be ok, if you don't have enough 6 plug PEG connectors.