@JamesG said: When I ask the system what it thinks the capabilities are, again I get Gen1x1: cat /sys/bus/pci/devices/0000:00:08.0/current_link_speed 2.5 GT/s PCIe cat /sys/bus/pci/devices/0000:00:08.0/current_link_width 1 cat /sys/bus/pci/devices/0000:00:08.0/max_link_speed 2.5 GT/s PCIe cat /sys/bus/pci/devices/0000:00:08.0/max_link_width 1 This information is actually crafted by QEMU, it doesn't represent the actual real device PCI state; you should check this from Dom0 which should be closer to reality.