Replacing a Dell Optiplex 3020 SFF PSU

Re: wondering if I’m able to change the power supply unit with a normal 500w power supply and use a adaptor for the motherboard power pin to power a bigger graphics card. I’m not too fussed about it being on the outside of the case.

yes certainly.  A regular ATX psu outside case with a generic 24 to 8 pin adapter will do the job for you.  SFF can only accommodate low profile graphics card.

 Having psu outside case also creates more room inside case for a thicker double slot width graphics card.

one downside of having an open case is the front to back air flow is disrupted.

all in all, it may be better in the end to move everything to a new ATX case, but that could be a future project to think about.