i just got done building a gaming rig, and noticed my second graffics card is running 4x. its an asus sabertooth 990fx, and i'm running radeon 6770's in crossfire. ( 6770, i know, but i had one in my old computer and salvaged it and decided it was cheaper to buy another one and run xfire, rather than buy a higher end card) is there something i have to do in the bios to set it up as 16x. i am running the cards in slot 1 and 3, which are both 16x.