AMD Precision Boost Overdrive (PBO) was introduced back with AMD's 2nd generation Ryzen CPUs and worked as an automatic overclocking feature which raises both voltage and frequency when certain conditions are met, like power and thermals.
With the upcoming Ryzen 3000 series CPUs, AMD has further improved the PBO feature allowing these CPUs to hit higher single-core boost clocks, by up to 200MHz, as well as deliver standard all-core boost clocks. This, in turn, should both offer increased single- as well as multi-threaded performance.
AMD's Senior Techincal Marketing Manager, Robert Hallock, explains in the video below that thanks to Zen 2 cores and the new 7nm manufacturing process, the new PBO on Ryzen 3000 CPUs, when paired up with an X570 motherboard, can hit higher boost clocks if the VRM is capable of delivering additional power. Of course, there are other conditions and the maximum boost will certainly vary, but, nevertheless, it is definitely a nice feature to have.
As you already probably know, AMD's Ryzen 3000 series CPUs are expected to hit retail/e-tail shelves on July 7th, and this includes a total of five SKUs, from the high-end 12-core/24-thread Ryzen 9 3900X, priced at $499, down to 6-core/12-thread Ryzen 5 3600, priced at $199.