I have the same psu, if you look at the box pictures and your cables coming out of the psu you will have a 6pin pci-e and a 8 pin pci-e. the 8 pin has the same 6pin and a flex 2pin attached for cards that DO need a 8 pin pci-e. that 8 pin can act as a 6 pin.
6 pin pci-e are rated for 75 watts
8 pin pci-e are rated for 150 watts
So the 8 pin can stand in place and be used for 6 pin when needed.
Use the 6+2 one in picture