Consciousness and simulation is the different things. Efficient? What are the criterias of efficiency? Faster calculations means better consciousness? Nah. And don't you know that biorobots are the best form of life? Biorobot don't give a fuck about sun bursts and don't give a fuck about power shortages. He can consume a big variety of energy sources and can resist EMP. Metal silicon-based machines is a failing dream of previous millenium.