I'm interested in purchasing a new 970 card but noticed this board only supports PCI-E 2.0. Even looking at the GTX 600 and 700 Series they are all 3.0 as well. How much of a performance loss will i see using a 3.0 in a 2.0 slot?

So i have the crosshair V formula Z board im running Patriot PXD38G2400C11K(XMP) 8GB ( 2x 4GB ) they are both in the red slots i have the most current bios 1101 but for some reason the system thinks my ram is only 800 instead of 2400 specsProcessor A...