Eli5 Why do computer chips warm up?
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I had always wondered the same during my gaming days until I actually read about how microprocessors work. So, the process is simple yet beautiful. The only operations a transistor is capable of performing are switching ON or OFF. A huge number of transistors make up a microprocessor or a chip. There are two heating effects that happen, namely,
Joule heating: This happens when electric current flows through the resistive material in the chip and energy is lost as heat. This phenomenon, also known as “Ohmic heating” or “resistive heating”. It is described by Joule’s first law: H = I^2 * R * t, where H is the heat energy, I is the current, R is the resistance, and t is time.
The more current that flows, or the higher the resistance, the more heat is produced. This is an unavoidable byproduct of electrical resistance in any material.
Switching loss: Modern microprocessors contain billions of transistors, which are essentially tiny switches. As these transistors switch on and off to perform computations, they use power. Some of this power is not fully utilized and is wasted as heat. This loss occurs every time a transistor switches state, and with billions of transistors switching billions of times per second, it adds up.
Hence, as powerful a microprocessor gets, it requires an equally efficient cooling technology. I hope this helps.
For the same reason light bulbs get hot: you pump a lot^(*) of electrical current through them (which vibrates the atoms in the wires). Those vibrations generate heat, which has to get moved *somewhere else*. Otherwise, the wires melt.
^(*)Where “lot” is, of course, relative.
All computers are made of transistors. A transistor is basically a small bit of semiconductor material that current flows through and the flow can be turned on or off via another current. This lets each transistor act as a fully electrical switch that can turn a current on or off based on input from another current. If you have a lot of them, you can do fun things with this like use the currents being on or off to represent different numbers, and do math with them and stuff. But wait a minute, let’s go back to that first part: current flowing through a semiconductor. An obligatory byproduct of that is heat. This the same effect that causes extension cords to heat up: when electricity encounters resistance, it releases some energy as heat. Moreover, whenever the transistor is switched from on to off or vice-versa, it isn’t instantaneous. There’s some amount of time that the transistor is allowing electrons to flow, but not freely. The higher the resistance, the more the heat. So, all transistors heat up some when there is current going through them, and the heat up more the more often they switch on and off.
All of this is pretty negligible though because transistors are pretty small and the currents involved are pretty low. But if what if we want to use transistors to do more than just remember a handful of numbers? Well we need more than a few. Modern CPUs might have hundreds of millions to billions of transistors. So it adds up
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