The TUSB7340 EVM boards are PCI Express X1, therefore the boards can be used in any PCI Express Slot (X1, X4, X8, or X16) on a typical motherboard. The boards can be used in either a PCI Express Gen1 (2.5Gbps) or Gen2 (5Gbps) slot. Due to the speed of USB3 (5Gbps), the performance of the TUSB7340 is negatively impacted if the EVM board is used in a PCI Express Gen1 slot. For this reason, TI recommends to always insert the EVM board into a PCI Express Gen2 slot.