The PEX10 PCI express expansion module routes one x16 PCI express mechanical interface comprised of four x4 PCIe Gen3 or Gen2 electrical links directly from the second processor (CPU1) on a dual-processor single board computer such as the Trenton BXT7059 or JXT6966 down to the expansion connector on a backplane such as the Trenton BPG8150, BPX8093, or BPC7041.