Hello, I was just wondering out of curiosity, if I have a system that requires 400W minimum, could I rig 2x 250w power supplies together to get 500W? just for the record I am fully aware that I could just buy a better psu
It wouldn't create a 500W power supply, but it would allow you to spread the load of your system between the two power supplies. This requires a "PSU bridge" (not exactly sure what they're called) that makes it so that both are activated at the same time.
Everything works better if it's all powered on at exactly the same time. The bridge will ensure that. You could do the same by doing some splicing and such, but that introduces the chance of other things going wrong.