A computer includes a processor, a PCIe-compatible interface bus that includes a root that is connected to the processor, and a routing complex that is connected to the root and is controlled by the processor. The computer also includes a first interface slot that is connectable to the root by the switches, a second interface slot that is connectable to the root by the switches, and an extended interface slot that is connectable to the root by the switches. The switches are configured based on properties of a first peripheral device to define a first switching configuration when the first peripheral device is connected only to the first interface slot and to define a second switching configuration when the first peripheral device is connected to both of the first interface slot and the extended interface slot.