Rpeak values are calculated using the advertised clock rate of the CPU. For the efficiency of the systems you should take into account the Turbo CPU clock rate where it applies

I’m gonna speculate, but I don’t think these systems can run all cpu cores on turbo due to power and thermal limitations and because that wouldn’t be good cost/processing power wise (since you need excessive cooling to do that). Rather, they fire turbo on groups of CPUs, allowing the CPUs to cool down till the sequence wraps around

So, I think rPeak is the processing power achieved when the computer is turboing a large chunk of CPUs

Sorry for my messy writing, I’m a little tired