The HWmonitor that I have used above is 1.23.0 driver version 136 which I have had since 2013, seems to work fine for the FX series although it is more to do with the chipset on the motherboard.
I had my FX8350 in an ASUS M5A99x R1.0 motherboard when I first had it, It was 2012 silicon, one of the first. The mobo / CPU would bench at 5GHz readily x264, cinebench etc. But would only prime at 4.5GHz I could prime on 4 workers at 4.9GHz. I could game at 4.7GHz.
Therefore I believe that the motherboard is fine and the cooler is suspect. I far prefer large air coolers (or custom water) however I am back to air cooling now. I would go for a Phanteks twin tower over any AIO cooler out there. The heligon is good, but I got it as B grade.
Yeah prime for me limited my overclock to 4.5ghz due to my motherboard, but cinebench and handbrake gaming I could manage 4.8-5.0ghz.
I've always used air cooling, and a mistake a lot of people make with gpu's and motherboards is replacing the air cooler with a water/liquid cooler but not having an additonial fan situated over the vrms and phases.