Asus Z9PE-D16 - Manual (Page 36)

2-18 Chapter 2: Hardware information
PIKE slot (from CPU 1)
PCIE 2 (x16 Gen3 link, Auto switch to x8 link if PCIE 1 is
occupied, White, from CPU 1)
PCIE 1 (x8 link, Gen3 link, MIO supported, White, from CPU 1)
PCIE 6 (x8 Gen3 link, Balck, from CPU 2)
PCIE 5 (x16 Gen3 link, Balck, from CPU 2)
PCIE 4 (x16 Gen3 link, White, from CPU 1)
PCIE 3 (x16 Gen3 link, Balck, from CPU 2)