Apple Xserve (Early 2008) - Manual (Page 38)

38 Chapter 2 Installing or Replacing Components
Installing a PCI Card
The Xserve has two PCI slots:
 Slot 1, which accepts half-length (6.6 inch) PCI Express or PCI-X cards
 Slot 2, which accepts full-length (9 inch) PCI Express cards
To install a card, you first insert it into a matching riser, and then install the riser into
the slot. The type of card you can install depends on the riser you use:
 A PCI Express x16 riser can only go in slot 2, and accepts only PCI Express cards
 A PCI Express x8 riser can only go in slot 1, and accepts only PCI Express cards
 A PCI-X riser can only go in slot 1, and accepts only PCI-X cards
Connectors on PCI Express x8 riser Connectors on PCI Express x16 riser
Connectors on PCI-X riser