> Power Behaviour: No Real TDP, but Wide Range Actually, TDP stands for "Thermal Design Power" and is not a range. It means "I, the designer, designed it so th

> Power Behaviour: No Real TDP, but Wide Range Actually, TDP stands for "Thermal Design Power" and is not a range. It means "I, the designer, designed it so that this is maximum amount of waste heat as it can safely produce continuously in normal use". It is mainly limited by its physical package and maximum temperature at which the internal components can run. That you can't observe that max power is due to the fact that those various applications stress the CPU in various ways, not always being able to exercise all internal structures to their maximum potential, at the same time. > One should probably assume a 90% efficiency figure in the AC-to-DC conversion chain from 230V wall to 28V USB-C MagSafe to whatever the internal PMIC usage voltage of the device is. (This was regarding idle power usage) Highly unlikely. I design AC switching power supplies from first principles (and stacks of books). Efficiencies above 90% are normal for newer designs but the PSUs are designed to achieve these efficiencies above significant percentage of their design power. High efficiency at design power is important because it limits worst case waste heat which in turn makes it possible to create smaller PSU. But as PSU is a lot of tradeoffs, one of the tradeoffs that is taken is lesser efficiency at lower power where it doesn't matter as much. Typically, the lower load on the PSU as portion of design power the lower the efficiency. If the PSU is designed for 140 watt 90% efficiency, I would expect that at 7 watt it is actually much less efficient probably somewhere between 70 and 80 percent.