4 pci slots, 5 pci express 2.0 x1 slots (2.5gt/s), 6 pci express 2.0 x16 slots – Asus P7P55D Premium User Manual
Page 42: Pci slots -22, Pci express 2.0 x1 slots (2.5gt/s) -22, Pci express 2.0 x16 slots -22, Chapter 2
Advertising