Lenovo THINKSERVER 3821 - Manual (Page 151)

The system board is equipped with a PCI extender card that provides either one or
two additional expansion slots. The following illustration shows one additional PCI
Express expansion slot that is available on the PCI Express extender card, if
equipped.
1 PCI Express x8 slot 7
The following illustration shows two additional PCI-X expansion slots that are
available on the PCI-X extender card, if equipped.
1 PCI-X 1 slot 7
2 PCI-X 2 slot 8
Chapter 6. Locating Server Controls and connectors 143