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How effcient is your brain?

A high-end CPU these days uses nearly 100W of power. But it doesn’t have nearly the computing power of a human brain. AI is in good part, perhaps mainly, a software problem, but raw computing power seems lacking too. So how many of today’s CPUs would it take to build a computer with human intelligence? Say at least 10,000 Opterons.

This 10K CPU computer system would use 1MW of power. So how does that compare to a human brain? A person runs on 2000 Kcal / day.

At 86400 s / day this is 23 cal / s x 4.187 calories / J = 97 J / s. J / s are equal to Watts so this is 97 W.

Say 40% of the body’s energy is used by the brain. Then a person’s brain uses 40 W, as much a weak light bulb. Which is order-of-magnitude correct–your head is a little cooler than a weak bulb but the bulb is smaller.

So a human intelligent computer would use 1MW of power while a person’s brain uses 40W. The human brain is 25,000X more effcient than a computer. This says a few things about today’s computers. They are terribly inefficient, at least for the types of computations an AI needs to do. And today’s AI software design doesn’t capture the organization of biological computers. We have 1000 CPU systems today, and could build 10K CPU systems. But no system today is as clever as a mouse. Today’s AI may have crested the house fly brain goal post. But the lack is clearest in the hardware architecture.

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