AMD FX-8120 | techPowerUp CPU Database :rollani:
So check with the stock cooler what temperatures you have because it's not normal since your CPU runs stock at 1.425V... your motherboard undervolts to 1.416v, which is normal by the way.
That said, check how it behaves with the stock cooler with everything on auto and a bit of heat with OCCT or with AIDA64 in FPU mode (I recommend OCCT because it creates a folder where it logs/graphs the parameters of everything it has recorded)
And you send us some screenshots ;D
As for lowering the voltage... the same, if you want to undervolt make sure that OCCT is stable for you.
Regarding the Scythe Katana 4 I think it's a bit weak for a micro with a TDP of 125W, probably better than the stock (I don't know how much better) but in any case insufficient to calm the wrath of an FX.
Anyway you shouldn't worry about it getting to 67º, if the micro handles it well and doesn't do "Thermal-Throttling" then nothing happens... the problem is if it drops below MHz because you will lose performance but don't worry the CPU won't burn... unless you have disabled it in the Bios 