1) If the board power is >75W extra power is needed. According to spec a PCIe slot can't deliver more. Expect throttling without it.Why it even has 6pin PEG? Most probably it works fine without it. I do not see a tied VRM circuitry around it.
2) VRM circuitry is *almost never* near power connectors (what's there is fuses, shunts and monitoring stuff). Controlling power is easier when the VRM is close to whatever's using it.