Causes of heat build up

The amount of heat generated by an integrated circuit (e.g., a CPU or GPU), the prime cause of heat build up in modern computers, is a function of the efficiency of its design, the technology used in its construction and the frequency and voltage at which it operates.
The dust on the laptop CPU heat sink after three years of use has made the laptop unusable due to frequent thermal shutdowns.
The dust on the laptop CPU heat sink after three years of use has made the laptop unusable due to frequent thermal shutdowns.

In operation, the temperature levels of a computer's components will rise until the temperature gradient between the computer parts and their surroundings is such that the rate at which heat is lost to the surroundings is equal to the rate at which heat is being produced by the electronic component, and thus the temperature of the component reaches equilibrium.

For reliable operation, the equilibrium temperature must be sufficiently low for the structure of the computer's circuits to survive.

Additionally, the normal operation of cooling methods can be hindered by other causes, such as:

* Dust acting as a thermal insulator and impeding airflow, thereby reducing heat sink and fan performance.
* Poor airflow (including turbulence) due to friction that reduces the amount of air flowing through a case, possibly causing stable whirlpools of hot air in certain areas.[citation needed]
* Poor heat transfer due to a lack or poor application of thermal compounds.