Overclocking on B550 is pretty much the same as you would see on X570.
The Ryzen 9 3900X has a base clock of 3.6 GHz and boosts up to 4.6 GHz. Now that boost is only on 1-2 cores. By overclocking we can set all cores to run at the same speed all of the time. This will give us better performance, especially in multi-core workloads.
With this board we can do our overclocking a few different ways, we could opt to do it in the BIOS or using AMD’s Ryzen Master Software. We’ve decided to go with AMD’s Ryzen Master software as it is far less complicated for most users.
When it comes to overclocking I would suggest starting at the base clock of your processor and moving up in small steps. So for the Ryzen 9 3900X it would be 3700, 3800, 3900, etc. You are likely going to have to adjust your voltage as well. A good starting point is 1.33-1.37V Vcore. Each time you overclock using the Ryzen Master software use the “Apply & Test” when saving your setting.
Besides using the Ryzen Master “test” we also use use AIDA64 and CINEBENCH to make sure our overclock is stable, but any CPU-focused benchmarking program would work. When running the stability test / benchmark be sure to keep an eye on your temperatures as well. If your system does not boot up try upping your Vcore. If that does not help you could try settings your load line calibration higher.
After much testing we were able to get our Ryzen 9 3900X running at 4.2 GHz on all 12 cores at 1.35V! Which is only 100 MHz lower than what we were able to achieve on our X570 motherboards!
Our max temperature when running CINEBENCH R20 was 82C so this is not an overclock that I would suggest. You are likely going to want to bring it down to 4.1 GHz or even 4.0 GHz if you are using an air cooler like we were.