I'm planning on building a new system and can't decide between these two motherboards. I've chose my cpu which will be the AMD Phenom II X4 965 rev C3 and I want to us two ATI 5750 cards in crossfire mode. The Crosshair III suports pcie 2.0 x 16 dual whereas the M4a79XTD EVO supp orts pcie 2.0 x8. Is there enough diffence in the two modes to justify spending the extra money on the Crosshair III?