The CPU has an advertised boost clock of 4200MHz, which will apply for workloads that don’t fully load all cores at 100%. There’s minimal fluctuation in this frequency plot and it does not appear that any boost duration limits come into play.
For a better view of this,, we’ll plot each core clock individually and with a Y-axis constrained to just 4050-4200MHz. The point of this is to magnify the data. As observed here, pre-testing starts with cores bouncing off of the 4200MHz limited-core turbo while still in idle. Once the work begins, the cores take turns bursting up to 4125MHz and falling back to 4100MHz, with rare dips down to 4080MHz. We’ll keep drawing other cores as we go. There doesn’t seem to be a preference for which core boosts up to 4125MHz. A pattern emerges where cores 0 and 1 pass the ball back and forth, as do cores 4 and 5. Cores 2 and 3 appear to do similar. At the end of the day, they take turns boosting.