> but the efficiency cores are slower in the M3 vs the M1, I think that's only true when comparing M3 Pro vs M1 Pro (rather than the base M chips that each hav

> but the efficiency cores are slower in the M3 vs the M1, I think that's only true when comparing M3 Pro vs M1 Pro (rather than the base M chips that each have 4 efficiency cores), and only when running threads with a background-priority QoS setting. Testing like [1] has shown that macOS runs background threads on M1 Pro/Max efficiency cores at higher clock speeds to compensate for only having two of those efficiency cores compared to 4-6 for all the other chips. But when normal-priority threads spill onto efficiency cores because the performance cores are full, the efficiency cores run at full speed on all chips. [1] https://eclecticlight.co/2023/11/27/evaluating-m3-pro-cpu-cores-1-general-performance/ https://eclecticlight.co/2023/11/27/evaluating-m3-pro-cpu-co...