FOSS gamedev and creative worlds

I would like to connect 2 motherboards and make them one... Now how do I do that ( I am too cheap to buy daul socket unless I find it cheap)

Pretty sure that's impossible

It might to some degree work by software. You can run some programs/processes on one computer and other ones on the second computer. How far that works depends on the software. With Minetest, you could run server and client on seperate machines.

Even if you could physically connect your two boards you'd still have the same problems as with two machines - the software has to be able to deal with it. Very exotic and expensive server boards may be built so that they can be connected to the same power supply. With normal boards, that might be a very bad idea and result in destroyed hardware at best.

Better operate two computers and use one as server and one as client (the one with the better grapics capabilites).

Probably, you want to read this or this or this...

Buy two insanely expensive Xeons and their motherboard. :P

No seriously, why would you do that? Minetest client and server don't require a very powerful to be run at a good speed (any dual core CPU > 2GHz can do that).