Asus P5B manual Primary PCI Express x16 slot, Universal PCI-E slot max. x4 mode

We recommend that you install a VGA card on the primary (blue) PCI Express slot, and install any other PCI Express device on the Universal PCI-E slot (black).

Primary PCI Express x16 slot

The primary PCI Express x16 slot supports PCI Express x16 graphic cards that comply with the PCI Express specifications.

Universal PCI-E slot (max. x4 mode)

This motherboard also supports a Universal PCI-E slot with a maximum speed of 2 GB/s. The operating frequency of this slot changes,

depending on the type of PCI Express card you install. Refer to the table below and page 4-23 for details.

The figure shows two graphics cards installed on the primary PCI Express x16 slot and the Universal PCI-E slot.

If you install two VGA cards, we recommend that you plug the rear chassis fan cable to the motherboard connector labeled CHA_FAN1 for better thermal environment. See page 2-31 for the connector location.

Options for Universal	PCI Express operating speed
PCI Express slot
Auto	Automatically optimizes performance
	and functionality according to devices
	installed
x4 mode [fast]	User gets the best performance but this
	mode disables the PCI Express x1 slot
x2 mode [compatible]	Always runs at PCI Express x2 speed

•Some PCI Express graphics cards cannot operate on x4/x2 mode. We

suggest that you install these cards on the primary PCI Express slot (blue) to increase system stability.

•Some PCI Express devices cannot operate on x4/x2 mode.

ASUS P5B Deluxe 2-21