Sorry, there was someone else a few weeks ago who posted that they had left their PSU on the porch and had come back to find some of the 24pin cables were cut. Thought you were back. Soldering back together would be 100% better, just twisting them for low voltage low current is ok, but mobo's use lots of current, and you've just put a big resistor (the twist) in the cable, this should then reduce the voltage at the mobo end, hence it may not work.