OK dcgj - had someone who was sold a dual Xeon motherboard with a single CPU and the wrong RAM not long ago for a home computer non-gaming system. The dealer sold him this $550 board then didn't even know what RAM it used. Sent him 2 - 2GB modules.
I did find some useful info about the CPUs at Wiki, might read up some for hints. And search Newegg and others starting from the CPU/socket.