The FX processors can produce quite a bit of kick. I would recommend picking up an aftermarket cooler (water cooling isn't necessary, and the fan shouldn't cost you more than $35) to keep temps down while overclocking and you'll be fine.
What frame rate would you consider "bottleneck"? I have fx 6300 (5.0) and rx 480 8gb and I am able to max it out on 1080p with pretty constant 60. Haven't fully tested 1440p but medium settings ran really smooth, wayyyy better than my r9 380.