Silicon Graphics Origin 3900, User Manual, Page: 113 / 292

PCI and PCI-X Card Configuration Guidelines
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Important Installation Considerations
To maximize the operating efficiency of the PCI cards, consider the following
configuration guidelines before you install the cards:
• You can place one or two PCI cards on one bus, or one or two PCI-X cards on one
bus.
• You should avoid mixing cards that operate at different frequencies or in different
modes. If you have two cards of different speeds on the same bus, both cards
operate at the lower speed. If a PCI card and a PCI-X card are on the same bus, both
cards operate in PCI mode. Note the following examples:
• When one 133-MHz PCI-X card resides on a bus, the card operates at 133 MHz
in PCI-X mode.
• When two 133-MHz PCI-X cards reside on a bus, the cards operate at 100 MHz
in PCI-X mode.
• When two 66-MHz PCI-X cards reside on a bus, the cards operate at 66 MHz in
PCI-X mode.
• When two 66-MHz PCI cards reside on a bus, the cards operate at 66 MHz in
PCI mode.
• When one 66-MHz PCI card and one 66 MHz PCI-X card reside on a bus; the
cards operate at 66 MHz in PCI mode.
• When two 33-MHz PCI cards reside on a bus, the cards operate at 33 MHz in
PCI mode.
• When one 66-MHz PCI card and one 33-MHz PCI card reside on the same bus,
the cards operate at 33 MHz in PCI mode.
Note: When installing a PCI card, you need to shut down the operating system and
power off the PX-brick before installing the card.
Supported PCI and PCI-X Cards
SGI supports various PCI and PCI-X cards. These cards can be purchased from SGI or
another manufacturer. Ask your SGI sales representative for a current listing of PCI and
PCI-X cards supported by SGI.