FUD Zilla claims the NVIDIA nForce 680i chipset will never fully support the Intel Yorkfield processors:
Intel messed up its chipset business quite a lot as it did some last minute changes on Yorkfield and hadn’t informed Nvidia. The next time Nvidia got Yorkfield 45 nm samples they didn't work on Nvidia's 680i motherboards and it looks like they never will, at least not with the old motherboards.
Now Nvidia knows that it has to change the hardware on the motherboard and that all the existing Nforce 680i motherboards won't work with 45 nanometre quad core processors. We are still not sure if the 45 nanometre Wolfdale dual core CPUs will work.
So if you are persistent and you want Intel's 45 nm quad core and a Nforce motherboard to get some SLI action, then you need to get a new 680i SLI board or one of the new Nforce 780i motherboard that should be out shortly.