A 8.8" screen takes a lot less power.

When you say efficiency, I assume you’re factoring in performance of the device as well?

Maybe run Geekbench 6 and see.

I am not the original commenter; but they said "low-power user cases" i.e. very much not when running Geekbench; rather when it is near idle.

For my use case, I plug in a external SSD drive, setup an MP3 playlist, close the lid then put the computer into my backpack for low wattage listening. The M3 MBA uses about 50% more power than the P4 under this use case (usbc watt meter shows this).

FYI, AMD chips are notoriously bad at idle.