Consider what we started with - vacuum tube transistors - and the tasks being optimized, and learn about the first few iterations as processors were being devel

Consider what we started with - vacuum tube transistors - and the tasks being optimized, and learn about the first few iterations as processors were being developed. If each transistor is a bit then the number of transistors is the number of bits you can process per cycle. Each time you cut the transistor size in half, you can fit 4 times as many transistors in the same space, and it takes less time for signal to propagate between individual transistors. At a certain point, physics limitations will prevent shrinking the 2d area over which you can arrange transistors, so you'll have to start building into 3d arrangements. Bigger is slower and uses less transistors. It's also hotter, since the electrical connections are longer and thus have more resistance.