Depends what you mean by power efficient. Watts per low traffic website it's very efficient. CPU is generally not pegged at 100%. For watts per CPU cycle not

Depends what you mean by power efficient. Watts per low traffic website it's very efficient. CPU is generally not pegged at 100%. For watts per CPU cycle not as much, I agree. Say it takes 10W at full power (I've not measured). That makes it 1/10th of a normal CPU. But it's like 30-40 times slower.