The arrival of PBO on Ryzen 3000 series CPUs is not a surprise—AMD already revealed as much during its E3 livestream last month. However, since PBO has been limited to second-gen Threadripper CPUs up to this point, you may have missed what it is all about. Here is Hallock's explainer...
PBO is essentially an improved version of Precision Boost. It works by analyzing various factors of your Ryzen platform to apply an optimized overclock setting, based on various different factors. Importantly, it communicates with your motherboard to see what kind of VRM (voltage regulator module) current capacity is available. As explained in the video, the VRM is basically the middle man between the power supply and your CPU.
What this ultimately means is that certain setups will be able to hit speeds higher than what is advertised. For example, a Ryzen 7 3800X has a 3.9GHz base clock and 4.5GHz 'Precision Boost' clock. By utilizing PBO, you could conceivably see the CPU reach even faster speeds, perhaps in the range of 4.7GHz.
This is one of the ways that a buying a higher-end motherboard could prove beneficial. Top shelf motherboards typically feature a robust VRM arrangement, and are capable of supplying more current than your processor requires to run at stock settings. PBO taps into that additional headroom, allowing you to hit higher clockspeeds and potentially sustain those faster clocks for longer periods of time. Cooling is still important, of course.
PBO will work on third-generation Ryzen 5 and above processors, when plugged into an X570 motherboard. Those parts will land on retail shelves starting July 7. Let the fun begin.