I just picked up a Dual Xeon Motherboard, which suppots Socket 603 processors, I'm not familiar with any post Slot 2 Xeon processors, can someone explain the difference between 603 and 604 to me?
Actually the extra pin is for 533mhz/800mhz FSB vs 400mhz FSB http://www.acme.com/build_a_pc/connectors.html but it doesn't really do anything.. (and there were some 533mhz FSB 603 pin Xeons and 400mhz FSB 604 Xeons made just to confuze things)
So if you are going to use 604 pin Xeon's in your 603 pin MB it is recommended that the way to get it to work is to get a small drill (eg: http://www.smallparts.com/products/descriptions/mmcd.cfm ) and drill a extra hole in the socket. (instead of breaking the pin off the expensive processor)