It seems like a comparison of the battery life under light loads (accounting for the vast majority of the difference) multiplied by some unspecified single thread performance benchmark? But under light loads laptop battery life is dominated by things like the screen rather than the CPU, and on top of that the Macbook has a larger battery.

Meanwhile under the heavy loads that actually tax the processor the M4 somehow has worse battery life even with the larger battery and a nominally lower TDP.

Is the infamous efficiency not the processor at all and they're just winning on the basis of choosing more efficient displays and wireless chips?