Your're WRONG buddy---try the NEW ASUS Rampage--(X79) it has the 3.0X16 64 bit PCIe X16,16x,16x,16x using the new Intel IVY instead of the old sandy bridge.
I hate to burst your bubble but he was asking about AMD motherboards using the AM3+ socket. The newest AMD Chipsets are 970, 990X and 990FX based. None of those chipsets supports PCIe 3.0 nor do the AMD CPU's have PCIe implemented on the CPU. However, a PCIe 3.0 graphics card can be used in a PCIe 2.0 motherboard because it's backwards compatible to PCIe 2.0. It just runs at PCIe 2.0 speed.
The ASUS Rampage motherboards are high end INTEL motherboards that use the Intel Chipsets and intel sockets. Since the X79 Intel chipsets and Socket 2011 CPU's do support PCIe 3.0, those motherboards do support PCIe 3.0 graphics cards at PCIe 3.0 speed. Don't believe me? Look at this: http://usa.asus.com/Search/?SearchKey=Rampage
They are all Intel chipsets supporting only Intel CPU's.