If you compare energy per calculation intel server processors readily beat ARM server processors. When under constant high load, intel processors surely aren't

If you compare energy per calculation intel server processors readily beat ARM server processors. When under constant high load, intel processors surely aren't bad in regards to power consumption. So that can't be it. Maybe it's more about peak performance vs. average power consumption under very low load as you usually have in a mobile phone that's only used occasionally. For example when starting an app and scrolling you need very high performance but the rest of the time the CPUs are mostly idling.