Baratak400w at 12v is 33amps. It you are wiring a home circuit for 30 amps that requires #10, for 40amps #8. You are pulling almost as many amps as a stove and #8 isn't small. Go to Home Depot and look for yourself.Heck, that is half the amperage pulled by the starter in your car, think of the wire size there.those psu wires aren't very heavy, granted the run is shorter... but still. That is why Jay is seeing performance drop with a single cable split. I would guess in a long session on a single wire method, that wire warms and the voltage at the GPU side is measurably lower than on the PSU side.
