[nomel]

> How do brains do it with such a low amount of energy?

Physical analog chemical circuits whose physical structure directly is the network, and use chemistry/physics directly for the computations. For example, a sum is usually represented as the number of physical ions present within a space, not some ALU that takes in two binary numbers, each with some large number of bits, requiring shifting electrons to and from buckets, with a bunch of clocked logic operations.

There are a few companies working on more "direct" implementations of inference, like Etched AI [1] and IBM [2], for massive power savings.

[1] https://en.wikipedia.org/wiki/Etched_(company)

[2] https://spectrum.ieee.org/neuromorphic-computing-ibm-northpo...