Originally Posted by Zyro71
You are still drawing power from the board, correct? Even though PCIe and the CPU maybe wired differently, the power is coming from one area. + 4pin/6 or 8pin power connectors.
No, they are not connected electrically. CPU VRM is like a separate PCB when you talk about motherboard voltage delivery. The CPU VRM only has a connection to the 4/8pin socket. If this were not true, multiple powersupply rails would be useless as you would be shorting them together in the board.
A GPU on the other hand is built around sourcing power from multiple inputs. With specific sections of the regulation circuit being connected to specific inputs.