1080ti consumes much more power than regular CPU, so you can use CPU power connector (4x 12v yellow cables & 4x GND cables vs 3x 12v in PCIe connector, 33% more) to power GPU with a CPU-2xPCIe power adapter (available on sale) and use 2xMolex-CPU power cable to power CPU. I think that it's a most safe variant.
sure but what you say it false it s not 33% more, don't forget most of time the wire to cpu are smaller than the pcie so 4 wire doesn't mean better than 3 wire, specially in the poor adapter the wire are ridiculous tin
and he need to split then because still need to power his cpu