Asus P5B DELUXE P5B Deluxe user's manual - Page 47

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