alot of the core i7 motherboards got a 4+4 CPU power and some have two 4+4 CPU power. I asked a question on the same in the forum but no answer. Where do I find a power supply that does Dual 4+4 CPU Power or do I use two Power Supplys? First Forum question is here
The extra CPU power connector simply means the CPU can take up to 600W of power, mainly designed for extreme overclocking.
As for the PSUs, I know that the Corsair HX1000W, Cooler Master Silent Pro M850 & M1000, as well as the Silent Pro Gold 1000W & 1200W have dual CPU eight pin power connections.