The "clock speed" of a neuron is actually closer to 50ms-100ms (only about 10-20Hz for meaningful purposes) -- but you have about 100 billion of them, and they'

The "clock speed" of a neuron is actually closer to 50ms-100ms (only about 10-20Hz for meaningful purposes) -- but you have about 100 billion of them, and they're all working in parallel. The brain's building blocks are really slow relative to silicon; action potentials move at speeds measured in m/s.