slyu9213 :
Excluding games that use more than 4 Cores efficiently There will be only 1-3FPS of a difference between a FX 43XX vs FX 63XX. The same goes with FX 63XX vs FX 83XX. In your situation a 260X isn't fast enough where the FX 63XX would bottleneck the GPU. Even with a GTX 980 which is the fastest single gpu currently will perform the same in Far Cry 4 even if you use a 6350 or a 8350. Now if you were to compare the FX series to Intel's CPU there would be a big difference.
I don't agree that you will see a big difference using an Intel CPU at all. I think benchmarks would have you believe that is the case but it's not. Unless you are a competitive gamer / using a 144hz 1080p + monitor or running an SLI / crossfire rig with the aim of obscene FPS on a high res screen I don't think you can beat an FX6300 for gaming. They are cheap as chips and easy to overclock, you never really NEED an i5 for gaming in most people's cases. It just happens to be arguably the best chip for the job and if you can afford it great.