I'm trying to figure out how many pcie cards I can slot into the board. Looking at it it looks like I could fit between 3 to 4 of these compute units I'm looking to add. The wrx80 would be ideal. Is there anyway to add five pcie 3.0 compute unit cards in x16? Can't the pcie 4.0 slots support x32 pcie 3.0?

Can the board boot into the OS, without a gpu attached? I can just ssh in, and manage the computer from my desktop.