gasaraki :
Yes. if you have enough room for the other half of the 4 pins to overhang.
??
Round hole. Square peg problem.
What model PSU is it?
It sounds like you have the 8-pin EPS cable:
http://support.antec.com/support/solutions/articles/1000140052-what-is-this-connector-for-
MAY be an adapter.. I'll look.