Even though I haven't manually changed the clock speed for the CPU itself, leaving it at its stock 3.6 ghz (R7 3700X), it seems to always manage to reach 4.2 ghz when gaming, 4.4 ghz being its max boost clock speed. It seems to be doing a good job on its own for me since it hasn't crashed or anything. But is it safe to leave it on or not? And what if I want its clock speed to go no higher than 3.8 ghz? Will the PBO feature actually obey that or will it still go as high as it thinks the CPU needs to go? This article below recommends just leaving it at stock value and letting the PBO handle any overclocking it deems necessary for you. Its effect on its life cycle is my primary concern. The temperature never went beyond 60°C so.
"We recommend that you use the AMD Ryzen 7 3700X processor with its default settings. Let the Precision Boost feature do its thing to dynamically boost the operating frequencies, efficiently, whenever AMD's algorithms find it necessary. We made an analysis of Precision Boost and its performance impact, and we were pleasantly surprised with the results."