Hi there all. So my question is, I have the AX850 corsair psu and I just ordered my GTX 680 signature on friday. The card requires a 8pin and 6 pin power cable. The cables that come in the ax850 are kind of odd to what im used to. Their PCI E cables are 10 pin into dual 8pin with the hanging 2 incase you need a 6. Which is great. But my question is will that ONE cable with the dual 8 pin be enough to power the card? since it's going 10 into 14 pins ... or do I need to use 2 of the cables. Im assuming ONE of the dual cables is OK but not sure...

For that one single card, it should be fine.  The only difference between 6, 6+2 or 8 is the additional +2 pins are grounds... to prevent any potential overheating.  The 6, 6+2 or 8 can, in actuality, all deliver the same power even though the standards have two different ratings... it's all based around the additional 2 GND wires.
 
As an aside, on my Enermax, there's 12-pins on the PSU end and the PCIE PEG end is a 2x 6+2.  So obviously if there were an issue, it would be at the input side, not the output.  Rest assured, you'll be fine.