FWIW, things are standardized and keyed on the ATX board side of things. They aren't standardized on the power supply side of a modular power supply. Unless you've absolutely confirmed pinouts, never swap cables between modular power supplies. Fitment doesn't imply its actually going to put the right voltage on the right pins. Even within the same manufacturer pinouts have sometimes been different between models!

Also, some non-standard hardware looks very standard. (At least some) Dell motherboard/PSU connectors infamously are physically compatible (the plug fits the socket) with the ATX standard, but the wiring is sufficiently different that it can damage or be damaged by other hardware.