OC on a Ryzen is a mad dance. The cpu will boost according to voltage, temp and current levels. So lowering all 3 can actually get better boost speeds, upto a point. Best speeds are attained with the best balance of all 3, just raising or lowering any of the 3 can drop the boost, not necessarily raise it.
PBO does the balancing for you, far easier than trying it yourself.
Current levels are by far the biggest, most misunderstood, concern. Too many are stuck on Intel thinking. Raise speeds, fix voltages, check temps, done.
Ryzens can handle upto 1.5v at idle/extreme low current loads. 1.325v at middling current loads. @ 1.2v at extreme current loads. Not so bad except where do you define exactly what an extreme current load is? Just stress tests? Or gaming? Which games? Just CoD or BF5 or is CSGO and minecraft included?
So ppl are running high speed OC, with what they think is a safe 1.3+v, and burning out the cpu completely in less than 2 years.
Personally, I don't recommend manual OC on a Ryzen. Far better to set PBO, PBO1 or even PBO2 and let the cpu give you its best speeds according to how much cooling you can give it.