> a neuron can fire at like 1Hz and modern CPUs operate in the GHz range.
This comparison doesn't make much sense - computers have a very small number of cores, let's say 10, and brains have 86 billion neurons. 86 billion things operating at 1Hz is also in the GHz range. This is leaving aside the issue that a CPU cycle and a neuron firing are doing completely different sorts of work - comparing them is kind of nonsensical in the first place.