Comment by dzaima

Indeed a single thread is most simple to reason about, but if you have a single task that can already use 2 cores uniformly, going to 8 cores (assuming enough workload) should be a pretty clean 4x speedup (as long as you don't run into memory bandwidth limits, but that'd cap the single-threaded code too).

But the performance difference between E-core and P-core perf is way less than 4x; the OP article shows a 1.6x/1.7x difference in SPEC for skymont vs lion cove, and 1.3x/1.7x for crestmont vs redwood code; and some searching around for past generations gives numbers around 1.4x.

Increasing core counts being a much more area- and energy-efficient way for hardware to provide more total performance than making the individual cores faster is a pretty fundamental thing.