1.1 x PCI Express x16 slot, running at x16 (PCIEX16) (Note 3)
2.1 x PCI Express x16 slot, running at x8 (PCIEX8) (Note 3)
3.3 x PCI Express x1 slots (All PCI Express slots conform to PCI Express 2.0 standard.)
4.2 x PCI slots
Note 3) For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot. The PCIEX8 slot shares bandwidth with the PCIEX16 slot. When PCIEX8 is populated with a PCI Express graphics card, the PCIEX16 slot will operate at up to x8 mode.
So in crossfire they would be 8X