anyone is using a 6pin-to-molex adaptor to distribute the current to prevent overheat? does it work?

There already stands concern with drawing 400W of power over 3 wires, I would hazard a guess that trying to pull that type of power over 2 wires is not very smart.
I read the previous posts and found ppl are discussing on a PCI-e 2-to-1 adapter. I thought such 6pin-to-molex is with the same function to evenly distribute the elec current to prevent overheating. Besides, the 6pin-to-molex cable is much easier to get than 2-to-1 PCI-e.
Could you provide the link on the hazard using three wires?