if the ps has a 24 pin connector and a 4 pin connector, and the mobo has a 20 and a 4, do i just let the extra 4 on the ps connector hang off and connect the other 4 pin as well? It says it's for amd and intel both.
Yup. You need that square 4 pin connector to power the cpu properly. If your mobo has a 20 pin main socket and your power supply has either a 24 pin OR a 20 pin with an additional 4 added pin tab (which makes it a 24), both will work. You need that square separate 4 pin to be installed in any event, or your system will likely not even POST.