An advanced PCI express board assembly is mountable in a PCI express slot. The assembly includes a main board that is attached to an adapter board by a connector section that includes mechanical and electrical connectors. When the main board is attached to the adapter board, the plane defined by the main board is parallel to, and laterally offset from, the plane defined by the adapter board. The adapter board is connectable to a female PCI express connector in the PCI slot. When the adapter board is connected to the female PCI express connector, the main board plane is perpendicular to the motherboard and is laterally offset from the PCI express slot. More and larger components can be placed on the main board while the assembly remains within the reserved PCI express space.