Asus KFN5-Q/SAS - Manual (Page 42)

ASUS KFN5-Q Series 2-21
2.5.6 PCI Express x8 slot (x8 link)
The onboard PCI Express x8 slot provides x8 link. This slot is designed for
various server class high performance I/O add-on cards like SCSI RAID card,
and fiber-channel card.
2.5.5 PCI Express x16 slot (x8 link)
This motherboard supports PCI Express I/O cards that comply with the PCI
Express specifications. The figure shows a graphics card installed on the PCI
Express x 16 slot.
A PCI Express x16 add-on card inserted to the onboard PCI Express x16
slot runs at x8 speed only (hardware limitation). Make sure that you use
a PCI Express x 16 add-on card that supports x8 speed.
PCI Express x16 slot
PCI Express x8 slot