Hello, well that part is not a motherboard but a daughter-board for a Dell PowerEdge C8000 series server.
It normally sits in a metal cage and is one of several compute "sleds" that can be placed in one. Usually you would have something like a Dell PowerEdge C8000, C8220, C8220X or C8000XD server with up to eight single wide sleds or four double wide sleds (with hard drives) in them. The server has a back-plane that these daughter-boards plug into and that back-plane gets its power from a set of redundant power supplies. The sleds can be hot swapped in case one fails and since some of the slots can be empty, more can be added. Think of it as a array of computers instead of hard drives.
I don't really recommend trying to do anything with them unless you already have one of those servers or you have tremendous amounts of spare time and a degree in Electrical Engineering. All input / output as well as power for those boards is meant to go through the back-plane board, which was developed for that purpose.
If you want to go down the dual CPU path, you should try something else. You can get Dual CPU EATX motherboards starting at around $300, and they can run in most full tower cases with a workstation grade power supply.
Good luck!