I built an FX-8350 with 2x R9-390 gaming rig a few months ago... At the time, I decided to go the cheaper route gaming. After getting the FX-8350 stable at 4.8GHz, I still was not happy with the performance of the machine. I ended up swapping out the GPUs for a GTX-1080. The performance was much improved but still wasn't where I would have liked to see it.
I started researching an Intel build and game up with this current machine. The i5's performance for gaming looks very promising at this time.
As a baseline, below is the highest single core score I achieved. Unfortunately, running at this speed was not entirely stable.
FX-8350 @ 4.86GHz (Unstable)
Single Core 3199 / Multi Core 11,765
My every day overclock was slightly lower but extremely stable.
FX-8350 @ 4.8GHz (Stable)
Single Core 3,175 / Multi Core 11,789
After the fresh build and all drivers installed I ran a baseline bench. I was expecting a significant improvement over the AMD processor; I was not let down.
Stock i5-7600K @ 3.8GHz (4.2GHz Boost)
Single Core 4,986 / Multi Core 12,949
Something that was a little more surprising to me was the increase in performance shown on the GTX1080 with the Intel build. It trailed slightly below my overclocked scores (CPU + GPU).
GTX 1080 (+200 / +400) / FX-8350 @ 4.8GHz: 209,887
GTX 1080 (Stock) / Intel i5-7600K (Stock): 206,340
I am very excited to see the gains this GPU sees when overclocked.