In the description of the Fatality mobo says it can handle 3 way sli, but in some review I have read it says the PCIE would be 8x4x4. Is this true?

Currently I am running 2 gtx 470 on 5760x1080 resolution and want to add another card to increase my frame rates. Would I see a big performance hit running the PCIE at those speeds?

thanks in advance