Why Reviewers Underestimate the Power Consumption of Apple Silicon Macs

Many reputable websites and channels “measure” the power consumption of Mac computers using apps like Max Power Gadget or asitop. These apps are built on top of the powermetrics MacOS facility.

However, in the man pages of the facility it is clearly explained that the readings are estimated and not measured values and that they shouldn’t be used for making power consumption comparisons.

In my performance investigation studies I found that the reported CPU and GPU power consumption is vastly underestimated: in case of the GPU the reported value is just over a third of the actual consumption, as is explained in the video.

It is unfortunate that said reviewers do not bother to sanity check the numbers with a power meter and thereby perpetuate misleading information on Apple silicon performance/Watt.

In a prior investigation, where I did extensive Linear Algebra performance investigations on the M4 Max, I found that it’s CPU performance/Watt in dense matrix multiplication is well below that of Ryzen 9950X, when the computations are carried out on its Neon vector units. Similarly for Apple’s M4 Max GPU vs nVidia last gen RTX 4090.