Is RAM Fast Enough for Brain Modelling?
Once we’ve got our model in RAM, we can get the CPU to do something with it. The neurons in your head signal each other fairly slowly, but they do it all in parallel. So, even though a neuron might “fire” only 5 or 6 times per second, you’re talking about 100 billion of them working in parallel, so you’ve got quite a bit of processing going on. Normally the way someone might look at this problem is to start with the number of axons and figure we need to run short bit of computer code across each one a few times a second. If we start with our figure of about 1016 axons and figure each scan across an neuron or axon might take roughly 10 microprocessor instructions on each pass, and that gets us in the ballpark of 217 floating point operations, or about 10 petaflops. No surprise, this is spot-on with Ray’s calculations. But we’re already anticipating super-computers with more than this range of processing power… At that scale, we should be seeing HAL 9000’s pop up around us soon. We’ve al
