Guide to Laptop Cooling Systems: Heatsinks, Vapor Chambers, Fans, etc

This is the the first part of the Laptop Cooling Systems series post. This part will go over the computer jargon and the mechanisms used in cooling systems. Everything here will be explained in layman terms so that the average Joe can understand all the jargon on youtube reviews, amazon reviews, this website reviews, etc.

1. Heatsinks

A heat sink is a metal component placed on top of a laptop’s processor (CPU or GPU) to absorb and spread heat away from these parts. Think of it like a sponge for heat—it soaks up heat from the processor and spreads it over a larger area, making it easier to cool down.

This is done through thermal conductivity which refers to the material’s ability to conduct heat (e.g., metals like copper and aluminum have high thermal conductivity, making them ideal for heatsinks).

Here’s a simple breakdown of how it works:

1. Heat Absorption: The heat sink touches the processor directly, pulling heat away from it.
2. Heat Spreading: The heat sink spreads the heat across a larger surface
3. Cooling: A fan blows air over the heat sink, pushing the hot air out through vents, cooling it down even more.

1.1 Heatsink with Finned Arrays

Usually , heatsinks will have a a finned array which are  thin, closely packed fins as shown in the figure.

Now this is not always present in all heatsinks because it requires slightly more space. However, when available, these are more effective at dissipating heat. Imagine having a hot pot of boiling water you want to cool down as fast as possible without the use of a refrigerator.

Wouldn’t placing the boiling water in as many small little pots as possible be a faster way to cool it down? That’s exactly how this works. The water is basically allowed to interact with a bigger surface area that is at lower temperature if it’s moved to several smaller containers.

2. Vapor Chambers

A vapor chamber is an advanced cooling component that helps move heat away from the CPU and GPU quickly and efficiently. Think of it as a flat, hollow plate with a small amount of liquid (usually water).

Here’s how it works:

1. Heat Absorption: When the CPU or GPU heats up, the liquid inside the vapor chamber evaporates, turning into vapor and absorbing the heat.
2. Heat Spreading: The vapor spreads across the chamber, evenly distributing the heat across its surface.
3. Cooling and Condensation: As the vapor cools, it condenses back into liquid, which flows back to the heat source to repeat the cycle.

Vapor chambers are usually placed directly over high-heat components, like the CPU and GPU, to cover a large surface area. This setup is common in gaming laptops and high-performance workstations.

3. Thermal Paste and Liquid Metal

Thermal paste and liquid metal are materials applied to the CPU or GPU and the heatsink to improve heat transfer as shown below:

 

 

The purpose is to fill ANY gaps between the CPU/GPU and heatsink so that heat can be transfered efficiently.

What’s the difference between the two?

Just the material.

• Thermal Paste: are usually made of a silicon- or ceramic-based compound.
• Liquid Metal: are made of HIGHLY CONDUCTIVE ALLOY (they make heat transfer more efficient). This is much more efficient than thermal pastes but it’s way more complicated to implement on a system and may damage components if not done properly. 

4. Heat Pipes

Heat pipes are thin, sealed tubes filled with a small amount of liquid (usually water).

How they work?

1. Evaporation: When the CPU or GPU heats up, the liquid inside the heat pipe evaporates, turning into vapor that absorbs the heat.
2. Heat Transfer: The vapor moves along the pipe to a cooler area, usually near a fan or vent.
3. Condensation: As the vapor cools down, it turns back into liquid and flows back to the heat source, ready to repeat the process.

Heat pipes are placed directly over hot components and connected to a cooling system, like fans, to help dissipate the heat. 

Vent placement in a laptop plays a CRUCIAL role in making an efficient cooling system.

Vents are placed to separate intake and exhaust areas. In the sketch I made above, they’re the gray colored rectangle shaped objects.

Cool air typically enters from the bottom or sides, while hot air is exhausted through the rear or sides. :

Now…ideally a laptop should have as many vents as possible however this isn’t always practical. For example, a small thin laptop may not need as many vents as much as a gaming laptop. Having too many vents on thin small laptops can jeopardize the chasis resistance to shock as well as being more prone to accumulating dust.

Rear Vents: In high performance laptops, larger and more vents are used to ensure maximum airflow, while rear vents direct heat away from the user. Comming in gaming and high-performance laptops, as rear vents direct heat away from the user, especially during long sessions.

Side Vents: Positioned on the sides of the laptop, often near the CPU or GPU, side vents help exhaust hot air directly out of the laptop’s sides.

Bottom Vents: Bottom vents allow cool air to enter the laptop, often working with rear or side vents to create a full cooling cycle. Comming  on thin and portable laptops (MacBooks). However, they can be obstructed if the laptop is placed on a soft surface, like a bed or lap.

6.1 Gaming Laptop Vents

Ideally, a high-end gaming laptop vent configuration should be something like this:

• Rear Exhaust Vents: 1-2 vents for efficient hot air expulsion.
• Side Exhaust Vents: 1 on each side, aiding in heat removal.
• Bottom Intake Vents: Primary source for drawing in cool air.
• Optional Front Intake Vents: Can enhance cooling but should be carefully positioned.

6.2 UltraBooks Vents

Since ultrabooks prioritize portability and often don’t handle as intense workloads as gaming laptops, their cooling design is more compact and less aggressive.

• Exhaust Vents: Typically, 1-2 exhaust vents (primarily at the rear) are sufficient for ultrabooks, as they usually generate less heat than high-performance laptops.
• Intake Vents: Bottom vents are often the main source for cool air intake. One or two intake areas are generally adequate.

7. Example: Gaming Laptop Cooling System

The laptop below runs on a Core i5 8250U and a MX450. Notice that there is only ONE FAN in the entire cooling syste, There’s only ONE HEAT PIPE and the heat sinks/vapor chambers sit on top of the CPU/GPU.

This laptop only lasted me ONE year. It died in the heat of summer. Partly my fault but also the cooling system was not efficient. There should be at least TWO fans each dedicated to the GPU and CPU. Also one heat pipe (this reduces surface area for cooling) is not ideal.

Lastly, the vents on this laptop was also a problem:

• Only rear side vents/no side vents.

 When Buying a laptop off this website or any website, it’s always a good idea to check the vents just by looking at the laptop chasis as well. If it’s a gaming laptop, there should be several on all sides. 

Author Profile

Miguel Salas

I am physicist and electrical engineer. My knowledge in computer software and hardware stems for my years spent doing research in optics and photonics devices and running simulations through various programming languages. My goal was to work for the quantum computing research team at IBM but Im now working with Astrophysical Simulations through Python. Most of the science related posts are written by me, the rest have different authors but I edited the final versions to fit the site's format.

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