Asus P8B WS - Expansion Slots

2.2.5 Expansion slots
Ensure to unplug the power cord before adding or removing expansion cards.
Failure to do so may cause you physical injury and damage motherboard
components.
Slot No. Slot Description
1 PCIe 2.0 x16_1 slot (single at x16 or dual at x8/x8 mode)
2 PCIe 2.0 x16_2 slot (x8 mode)
3 PCIe 2.0 x1_1 slot
4 PCIe 2.0 x16_3 slot (x4 mode)
5 PCI1 slot
6 PCIe 2.0 x16_4 slot (x4 mode)
2-10 Chapter 2: Hardware information