If you look <A HREF="http://usa.asus.com/prog/spec.asp?m=P4C800-E Deluxe&langs=09" target="_new">here at the ASUS website</A> it says under Internal I/O Connectors that there is a 20-pin ATX Power connector and 4-pin ATX 12V Power connector on the board so I would assume that you need them both. Seems like most motherboards coming out these days need all the power they can get.
As for the power supplies, ask the store where you are getting them from. They should know what sort of connectors the power supplies have or can find out quick.
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