i removed the Enermax psu from the avalon but couldn't find any connectors in the cords included with my Seasonic that would fit the 2 white EPS ports shown in this picture.
is my only option to go out and buy special pci-e cords that have this type of plug on this end? i'm very surprised that my Seasonic didn't come supplied with these. am i missing something?
Those are the connectors you normally connect to a PC's motherboard to power the CPU - ie 8pin CPU connector. Your power supply should come with at least one! It is possible that your PSU is old enough that it was produced before manufacturers adopted the 12VEPS standard (which by the way is a server environment standard).
Oh also, a lot of motherboards come with a 4+4 connectors. You just join the two and they become 8 pin.
Edit: oops..did not notice ebereon's post. Just follow the link he posted and it will clear things up for sure.