I half agree with above post. I had an X4 750K (Athlon II) on a decent FM2+ board. Gigabyte G1 Sniper (green motherboard) with an MSI R9 270, and I think it had thermal throttling issues. The VRM's had no heatsink. When I overclocked, the benchmark results were worse than stock speeds on CPU, and I had plenty of fans and good CPU cooler.
HOWEVER. I am 1 part away from my complete new build. FX 6300, MSI 970 gaming motherboard AM3+. (same price range motherboard) and its so much better already, I'm using a piece of junk GT 605 graphics card for now, until 3 days when I order a GTX 960 4GB. Temps on VRM never go over 63c. And there seems to be no problems at all, benchmarks show the CPU to be awesome, and even a temporary OC to 4.3Ghz showed some impressive increase in benchmark results (passmark etc) So I would definitely praise the FX series processors. If you do go for FM2+, I would recommend a motherboard with VRM heatsinks, and even buy one of the APU's A10 7850k (whatever its called) paired with as far ram as possible, and coupled with a suitable GPU which it can crossfire with, and you will have very good gaming performance. I've seen stock A10s play BF4 at medium settings 1080p 30FPS. (with 2400mhz ram)