I have two motherboards, one has a keyboard (bios?) chip and the other has a spot for a socket to be mounted at that position.
What is the difference? What did they do? Can you add a socket/keyboard bios from a dead motherboard? If so, why would you want to?
Probably the discrete keyboard controller (not BIOS). If so, you can probably get one from a dead motherboard, as long as they are compatible controllers.
What advantage would it have though?
Well... If the board is working without anything in the socket, the KB controller must be integrated somewhere. So no advantage at all.
If the motherboard does not contain a discrete keyboard controller (KBC) chip, the KBC is integrated into the southbridge chipset. Ume Um8886BF chipsets contain the keyboard and PS/2 mouse controller integrated into them. I do not know what will happen if you attempt to plug in an 8042 KBC into an empty socket on a motherboard which contains an integrated KBC, assuming the empty KBC socket is wired correctly on the printed circuit board. I am uncertain if the Um8886AF contains an integrated PS/2 mouse controller, although it certainly contains an integrated KBC. The advantage of a discrete KBC is that you could swap out the KBC for one which has PS/2 mouse support and perform the mod, as revealed in this thread, Native PS/2 mouse implementation for 386/486 boards using the keyboard controller
Plan your life wisely, you'll be dead before you know it.
Award BIOS has several options for the Keyboard Controller chip, so you may have to alter that to make it work, otherwise I expect the system will ignore it. I expect AMI BIOS is the same but I've never had a need to take one of those to pieces.
They appear to be linked to the turbo pins and also seem to be used to switch the CPU in or out of Real/Protected modes.
