The fx6350 is going to perform better, it's typically on the same level as the i3-4130/4160 give or take. The 860K on the other hand is an APU with the iGPU disabled so it's really more comparable to the fx43xx line.
That being said, the FM2+ platform is newer and has more utility then the AM3+ platform. Previously there was a cost argument but there has been several solid 970 boards made. Looks like OEM's stopped treating the 970 as a trash part and using cheap VRM's and other low quality components for their boards. So the verdict, in a strictly gaming context, would be the fx6350. Currently single GPU's are saturating a PCIe 2.0 16x slot and that would be the only gaming related difference between the two platforms.
What is the purpose of the question? Is there a specific build in mind or just an academic question?