Hi SkmCry,
I have the same motherboard, and the same chip (6900k), also tried using adaptive voltage, set to 1.20 and set the multiplier to 4.0 ghz. I end up with the same voltage as you do under load. I updated the BIOS and it did not help. I just wanted to know if you found any solution besides using a negative offset (which also lowers the idle voltages).