Yeah, modern CPUs vary frequencies and you have to be very very careful about how you measure to account for this. This had already been true for more than 10 y

Yeah, modern CPUs vary frequencies and you have to be very very careful about how you measure to account for this. This had already been true for more than 10 years now and should be muscle memory when benchmarking but it can be easy to overlook and some people don’t know. It doesn’t surprise me that someone hypothesizing that Python automatically executes different lines of code on different cores might make this mistake as they don’t have a good mental model of how the code they run executes on their machine. As you note they probably made other methodological mistakes too.