I trust that the Apple benchmarks include all such effects. I'm less convinced that the RISC-V "projections" include them. SPECint2006 is supposed to be measured with real memory and an OS. Per-GHz numbers can't accurately reflect main memory latency, since its speed doesn't scale with the CPU clock.
Right, and "per GHz" numbers are also not very useful because you can't just crank up the GHz when you need performance. Even with the same process technology, you can't assume different microarchitectures will max out at the same frequency.
You're right, and remarkably Apple has found a major roadblock to clock speeds while using ARMv8.
M1's L1 cache is huge, as a workaround to ARMv8's poor code density. Larger cache means lower clocks, unfortunately there's no way around speed of light.
