Something I've realised is that a lot of people when starting a task they've never done, don't realise that fact and attempt to start and finish it all in one go anyways, rather than before starting realising you have no expertise and searching the web for "How to do: X" for more complex tasks this can be unsuccessful, but for simple tasks like installing computer parts people just wing it first time for some reason. 🤷♂️
Listen, I figured out how to do this at age 10 in 1994 before Google existed. It’s not fucking hard, OP’s guy must have been hammering those square pegs into round holes too. Some people just don’t have any common sense or problem solving capability.
I managed to plug the 4pin CPU_POWER cable into two corresponding ports. As in 2 pins from one port and two from the other, since they make up an 8pin port.
Surprisingly it was working but crashing randomly every half an hour.
These ports are shaped so that this is impossible, but I managed to do it anyway.
Those connectors are keyed, but only to prevent you from installing them backwards or rotated 90 degrees, and not from doing what you did. The "tombstone" shaped pins will fit in the square holes, but not vise versa.
Offsetting it by 1 pin side to side won't result in the loss of any smoke, because you will observe the wire colors and that all of the pins on the top edge are 12v positive and all the pins on the bottom edge are ground. You got away with what you got away with because you merely delivered insufficient current to the board, but not the wrong voltage or wrong polarity to the wrong place.