What stress tester are you using? I recommend OCCT on High for AMD FX chips. Prime95 has been kinda finicky lately so I dont use it anymore. Intel Burn Test is a good one too but in my experience OCCT has been the more reliable tester for my rigs.
If youre passing stress tests at 4.6 then keep the voltage where it is and tick the clock up to 4.7. When you cant go any higher, tick the voltage up til either you hit the 62C red line or you exceed 1.5V which is the most Id want to put to a FX chip 24/7. 1.45V is actually a little high so once you find your chip's limit, you might want to try some undervolting. If you could get down to say 1.40V and 4.7 or so on the clock, that would save you a lot of heat being pumped out into your room and shave a few cents off your power bill as well as prolong your chip's life expectancy a little.