By PCIE device I/O performance test, we recommend referring to performance tuning guide and setup preferred I/O to better achieve performance expectations. Regarding to preferred I/O setup in BIOS, we suggest to boot into OS to gather PCIE device bus/dev/function ID first. Then setup it in BIOS. For example, under Linux, you can use lspci to find device you would like to enable Preferred I/O mode.



In this example, we’d like to enable Preferred I/O mode on the SATA controller. The output of lspci will come in <bus>:<dev>.<func> followed by a description provided by the device vendor. Reboot to BIOS setting page and input the <bus> number. By this case, it’s “81”.