Size of copper atom is 0.2nm. We are already at 10nm fab processes. We can't really get too small otherwise it gets unstable and heat becomes a major issue. On

Size of copper atom is 0.2nm. We are already at 10nm fab processes. We can't really get too small otherwise it gets unstable and heat becomes a major issue. On the positive side, electric flows much faster than synapses and transistors are smaller than neurons. So with today's technology if we were to pack silicon parallel cores in size of human brain we'd have a much faster brain.