22 Are the Androids Dreaming Yet? gates so that they communicate in the vertical direction as well. Intel demonstrated the first three-dimensional chip in 2004, and these chips should begin to appear in our laptops by around 2020. Taking a chip into the third dimension solves the economic problem but adding logic gates to a 3D chip presents a new problem — heat. Heat is generated in proportion to the volume of the chip but it can only be lost through the surface area. Result: the chip overheats. Large animals have the same problem which is why elephants have huge ears, filled with blood vessels, they can flap to cool themselves and really big mammals, such as whales, live in the ocean. The thermal problem is now the biggest problem in most computer designs. One data point suggests we could solve this problem, the human brain. We pack huge processing power into our skulls without overheating by using a variety of techniques, including folding the surface of the brain, running each neuron very slowly and maybe even using quantum mechanics. A very recent discovery is that brains could be using quantum effects to transmit signals. If true - and the research has only been recently published - it means we may use a form of high-temperature superconductivity to avoid overheating. More on this in Chapter 4. Excluding exotic quantum effects, the main difference between computer and human brains is their processing architecture. Brains use slow, asynchronous logic to process information rather than the fast, synchronous type used in modern day computers. Logic gates in today’s computers work all the time, even when there is nothing to do. For example, if I multiply 2 by 3 on my laptop the entire multiply circuit, designed to work on 20 digit numbers will still operate, and, even worse, it will operate on every tick of the master clock even if there is nothing to multiply. The brain, by contrast, works only as it needs; unused gates don't operate. This gives a massive reduc