Why do processors emit heat?

Processors or CPUs (Central Processing Units) are the brains of every modern electronic device, from computers to smartphones. However, one of the most significant challenges in CPU engineering is managing the heat they generate. But why exactly do they emit heat, and how can we control it to maintain optimal performance?

What is a processor and how does it work?

Before we delve into the issue of heat, it is essential to understand what a processor is and how it works. A processor is an integrated circuit that performs mathematical and logical operations necessary for a device to function. It is made up of millions of transistors, which are tiny electronic switches that control the flow of electrical current.

Every time a transistor changes state (from on to off and vice versa), it consumes energy in the form of electricity. This energy is converted into heat due to the internal resistance of the semiconductor material (usually silicon) from which the transistors are made.

Why do processors emit heat?

1. Energy dissipated by transistors

As we mentioned, the transistors inside a CPU operate by the flow of electric current. Every time current flows through a transistor, a small amount of energy is dissipated as heat. This dissipation is multiplied by millions, given that a modern CPU can contain up to billions of transistors.

2. Operating frequency

A CPU’s operating frequency, measured in gigahertz (GHz), indicates how many work cycles it performs per second. The higher the frequency, the faster it can execute tasks, but the higher the amount of heat generated. This is because at higher frequencies, transistors change states more quickly, which increases power consumption and, consequently, heat generation.

3. Operating voltage

The voltage feeding the transistors also plays a crucial role in heat generation. Higher voltage allows the transistors to switch states more quickly, improving performance, but it also increases the power dissipated as heat. This is one of the reasons why CPU manufacturers are constantly working on reducing the voltage needed to operate the transistors without sacrificing performance.

4. Transistor density

As technology has advanced, processors have significantly increased their transistor count without increasing their physical size much. This increase in transistor density means that more power is dissipated in a small area, which contributes to CPU heat.

Solutions for heat management in CPUs

1. Heat sinks and fans

One of the most common solutions for heat management in processors is the use of heat sinks, which are metal parts designed to increase the surface area in contact with the air and thus better dissipate heat. Fans are used to improve air circulation, helping to remove heat from the heat sink and keep the CPU temperature at safe levels.

2. Thermal paste

Thermal paste is a compound that is placed between the surface of the processor and the heat sink. Its function is to improve heat transfer by eliminating small imperfections and air gaps between both surfaces, which facilitates better heat dissipation.

3. Liquid cooling

For high-performance CPUs, such as those used in workstations and advanced gaming systems, liquid cooling is an effective option. This system uses a coolant that circulates through water blocks placed above the CPU, absorbing heat and then dissipating it through a radiator.

4. Undervolting

Undervolting is a technique that involves reducing the operating voltage of the CPU. By lowering the voltage, the heat generated is reduced without significantly affecting performance. However, this technique requires careful tuning to avoid system instability.

5. TDP (Thermal Design Power) control

TDP is the maximum amount of heat a processor is designed to generate under maximum load. CPU manufacturers specify TDP to help engineers and users design appropriate cooling systems. Adjusting CPU settings to operate within its TDP can help prevent overheating.