Incorrect your board will do two card CF at x16 x16!
"2 x PCI Express x16 slots, running at x16 (PCIEX16_1, PCIEX16_2) (Note 1)
1 x PCI Express x16 slots, running at x8 (PCIEX8) (Note 2)
1 x PCI Express x16 slots, running at x4 (PCIEX4)
(Note 1) For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16_1 slot; if you are installing two graphics cards, it is recommended that you install them in the PCIEX16_1 and PCIEX16_2 slots."
This is one of the main reasons to buy an AMD 890FX chipset board!