Asus P5E64 WS Professional - Manual (Page 46)

2-20 Chapter 2: Hardware information
2.5.4 PCI slots
The PCI slots support cards such as a LAN card, SCSI card, USB card, and other
cards that comply with PCI specifications. Refer to the figure below for the location
of the slot.
2.5.5 PCI Express x4 slot
This motherboard supports PCI Express x4 and PCI Express x1 network cards,
SCSI cards and other cards that comply with the PCI Express specifications. Refer
to the figure below for the location of the slot.
2.5.6 PCI Express 2.0 x16 slots (blue)
This motherboard has two PCI Express 2.0 x16 slots that support two ATI
CrossFire™ PCI Express 2.0 x16 graphics cards complying with the PCI Express
specifications. Refer to the figure below for the location of the slots.
2.5.7 Universal PCI Express x16 slots (black)
This motherboard also supports two Universal PCI Express x16 slots with a
maximum speed of x4 or x1 link. The operating frequency of these slots change
depending on the type of PCI Express card you install. Refer to the figure below for
the location of the slots.
PCI Express x4_1 slot
PCIe 2.0 x16_1 slot (blue, @ x16)
PCI_2 slot
Universal PCIe x16_2 slot (black, @ x4 or x1)
PCI_1 slot
PCIe 2.0 x16_3 slot (blue, @ x16)
Universal PCIe x16_4 slot (black, @ x4 or x1)
Some PCI Express devices cannot operate on x4/x1 mode.