Some questions which we need to answer then :
1 ) What is the effective level of visual precision computed by those processors for Avatar, versus the level of detail that’s processed in the human visual cortex?
2) Is the synapse the equivalent of a transistor if we are to estimate the respective computing power of a brain and a computer chip? (i.e., is there more hidden computation going, on other levels? As synapse use different neurotransmitters, does that add additional computational capability? Are there processes in the neurons that similarly do computational work too? Are other cells, such as glial cells, performing computationally relevant operations too?)
The switching rate in a processor is faster than the firing rate of neurons.
All else being equal, a computer should be faster than an aggregate of neurons. But all isn’t equal, even when comparing different processors. Comparing transistors in a modern processor to synapses in a human brain yields many more synapses than transistors. Furthermore, the brain is massively parallel, and has a specialized architecture. For what it does, it’s well optimized, at least compared to how optimized our software and hardware are for similar tasks at this point.
For instance, laptop processors are general purpose processors, being able to do many different tasks they aren’t really fast or good at any. Some specific tasks may make use of custom made processors, which, even if their clock rate is slower, or if they have less transistors, will still vastly outperform a general purpose processor if they are to compete for the task they were custom-built for.