I would like the answer to this also. I don't doubt there is some, but is it enough to justify paying a minimum of $60 on a new motherboard? Based on the recent sub-$200 CPU article, there is no longer a price point at which an entirely new system shouldn't be Intel (sad, but the numbers don't lie); for someone with already higher-end AMD parts, with no budget for a complete upgrade / rebuild, will replacing a 2000MT/s mobo with a 5200MT/s mobo yield a difference worth the price? Does the answer change if two GPUs will be used?
I'd love to see just a couple of benchmarks; one CPU-dependent game (e.g. Skyrim) and one GPU-dependent title (e.g. Metro 2033). Testing with a 955 or 965, 4GB of RAM, and one or two HD6780 GPUs, how much difference is there, if only the mobo is changed?