Confused about the difference between "best" and "preferred" CPU cores? This article explains everything...kinda sorta.
To start off, the whole situation can be summed up with the following quote from AMD’s blog post today:
“This [Ryzen Master] star does NOT necessarily mean it is the fastest booster”
AMD goes on to clarify that there’s only a very loose relationship between what Ryzen Master showcases as the “best cores”, and what the AGESA firmware decides is the “preferred cores” that are communicated to the operating system.