Sorry for the noob question:

I'm setting up my freshly arrived S5. Power supply is Corsair rm750.

I keep reading everywhere (http://www.enthusiastpc.net/articles/00002/3.aspx) that maximum power output is 75W for 6pin connectors and 150W for 8 pin connectors.
How can the S5 draw ~500W using 4x6PCIe providing 75W each?
And can I power it with 2 cables of the type 1x8PCIe -> 2x6PCIe?

Thanks