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Appendix A: Troubleshooting
PCI Express Bus Width
Unlike the older PCI and PCIX bus interfaces, PCI Express (PCIe) is implemented
with serial links or “lanes.” As a consequence, PCIe slots come in different widths,
which are referred to as “by x” where “x” means multiplied. Currently there are 1x,
4x, 8x, and 16x widths. An 8x slot is composed of eight individual lanes. Each lane
has a 250 Mbps clock rate in both directions (full duplex).
Cards and slots are upward compatible: A smaller card will fit in (and work in) a
larger slot. That is, a 1x card will work in any slot, a 4x card will work in slots 4x and
up, and so on. Higher level cards cannot physically fit in a smaller slot; for example,
a 16x card will not fit into an 8x slot.
The SMC Server Adapter is designed for 8x operation, with a raw bandwidth of
20 Gbs full duplex on the Ethernet port. On some server motherboards, choice of
PCIe slot is important. This is because some slots (including ones that are physically
8 lanes or 16 lanes) may only support 4 lanes or may be limited to a lower bus
speed. In 4-lane slots, SMC adapters will continue to work, but will not achieve the
best performance possible. Users should consult their server manual for further
information.
Common Installation Problems
Problems are often caused by cabling errors, conflicts with other devices installed in
the same computer, or software that has been configured incorrectly. If you
encounter a problem with the SMC Server Adapter, use the following checklists to
identify and correct the problem.
If your computer cannot find the SMC Server Adapter, or the network driver does not
install correctly, check the following items before contacting SMC Technical Support.
• Make sure the card is securely seated in the PCIe slot. Check for any hardware
problems, such as physical damage to the card's edge connector.
• If there are other network cards in the computer, they may be causing conflicts.
Remove all other cards from the computer and test the SMC Server Adapter
separately. If you continue to have problems, remove all cards except the SMC
Server Adapter and your video card.