It is true that computers and other electronic devices ultimately convert all of the electrical energy they consume into heat. This is a consequence of the laws of thermodynamics, which dictate that energy cannot be created or destroyed, only transformed from one form to another.
At a fundamental level, the heat generated by electronic devices is due to the “Joule’s first law” (Joule heating), also known as resistive heating. The Joule heating effect describes the conversion of electrical energy into heat as a result of the resistance of materials to the flow of electrical current. When a current flows through a material with resistance, some of the electrical energy is converted into heat, which is then dissipated into the surrounding environment.
In electronic devices, the Joule heating primarily occurs in the components that perform computations, such as the CPU and memory. These components consist of microscopic transistors that use electrical signals to switch between different states, which performs the computation. Each time a transistor switches state, a small amount of heat is generated due to the resistance of the materials used in its construction.
This heat must be removed from the device in order to prevent the components from overheating and potentially failing. Traditional air cooling methods use fans and heat sinks to transfer heat from the components to the surrounding air, but immersion cooling methods use a liquid to more efficiently absorb and remove the heat.
While it is true that all of the electrical energy consumed by a computer is ultimately converted into heat, the amount of heat generated depends on the specific components being used and the tasks being performed. More powerful components or tasks that require more processing power will generate more heat than less powerful components or tasks.