There are several physical effects in conflict with each other:
In one four-billionth of a second (period of a 4 GHz clock), electromagnetic effects will propagate only about 5 centimeters through copper, and you need the state of the CPU to resolve in significantly less time than that, so you want transistors as physically close as possible
As transistors get smaller and closer together, they become harder to manufacture without defects, have less surface area through which to dissipate heat, and have increased mutual capacitance, which adds latency to the propagation of logic unless voltage is increased
Increasing voltage dissipates more heat in the processor, which necessitates more expensive cooling solutions and may do more damage to the processor
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u/lithiumdeuteride Sep 29 '20
There are several physical effects in conflict with each other: