[jacobp100]

I was looking into this. The M5 performance cores can be scaled down to match efficiency cores in performance and power usage.

I believe they lower the clock speed, limit how much work is done in parallel on each core, and limit how aggressive the speculative execution is so less work is wasted.

[aurareturn]

  The M5 performance cores can be scaled down to match efficiency cores in performance and power usage.

Source for this?

[pier25]

Not sure if this was available in previous gens but my M4 Pro can run in low power mode. It's amazing. I can work for hours and only use 10-15% of the battery.