esto es lo que figura en la pagina de Asus
http://www.asus.com.tw/products.aspx...11&l3=534&l4=0
2 x PCI-E x16 (blue @ x16 mode, black @ x4 or x1 mode) supports CrossFire Technology
2 x PCI-E x1
3 x PCI
Mira la info en la P5K64 WS
4 x PCIe x16 slot
2 x PCI 2.2
o en la Blitz Extreme
2 x PCIe x16 slot, support dual graphics solution
3 x PCIe x1 PCIex1_1 (black) is compatible with audio slot
2 x PCI 2.2