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During the 1960s, computer processors were constructed out of small and medium-scale ICs each containing from tens to a few hundred transistors.

For each computer built, all of these had to be placed and soldered onto printed circuit boards, and often multiple boards would have to be interconnected in a chassis.

The large number of discrete logic gates used more electrical power — and therefore, produced more heat — than a more integrated design with fewer ICs.

The distance that signals had to travel between ICs on the boards limited the speed at which a computer could operate.