What Is Liquid Cooling?

Liquid cooling is more efficient but more complex

Liquid cooling is a radiator for the processors inside a computer. Like an automotive radiator, a liquid-cooling system circulates a liquid through a heat sink attached to the processor. As the liquid passes through the heat sink, heat transfers from the hot processor to the cooler liquid. The hot liquid then moves out to a radiator at the back of the case and transfers the heat to the ambient air outside of the case. The cooled liquid travels back through the system to the components to continue the process.

Swiftech H140-X CPU Liquid Cooling System

What Are the Advantages of a Liquid-Cooled Computer?

Over the years, CPU (central processing unit) and graphics card speeds have increased. To generate the new speeds, CPUs employ more transistors, draw more power, run at higher clock rates, and thus generate more heat than ever before. Liquid cooling is more efficient than traditional heatsink technology at moving heat away from components.

In turn, this technology allows processors to run at higher speeds by keeping the CPU and graphics cards running within the manufacturer's temperature specifications. This efficiency is one reason extreme overclockers tend to favor this approach—in some cases, doubling processor speeds using very complex liquid-cooling setups.

Heat dissipates in liquid more efficiently than in air, particularly with an effective method of dissipating the heat through circulation.

Another benefit of liquid cooling is quieter operation. Most current heatsink-and-fan combinations generate a lot of noise because their fans work hard at circulating large volumes of air. In fact, many high-performance CPUs require fan speeds in excess of 5000 rpm; overclocking a CPU requires even more airflow over the CPU. Liquid cooling reduces the "engine noise" this generates.

What Does a Liquid Cooling System Look Like?

A liquid cooling system has two parts:

  • The impeller, which is a fan immersed in liquid to circulate it through the system. The liquid helps muffle the noise it generates.
  • A fan at the exterior of the case to pull air over the cooling tubes of the radiator.

Neither of these needs to run at very high speeds, so the system runs quietly.

What Are the Disadvantages?

As advantageous as liquid cooling systems are, they do have drawbacks.

They Need Space

Liquid cooling kits require a fair amount of space inside the computer case to work effectively. There must be room for items such as the impeller, fluid reservoir, tubing, fan, and power supplies. For that reason, liquid-cooled systems require larger desktop system cases. Much of the system can be outside of the case, but that takes up space in or around the desktop.

Recent closed-loop technologies have reduced the overall footprint over older systems, but they still require space. Specifically, they need enough clearance for the radiator to replace one of the internal case fans. Also, the tubes must reach from the component that needs to be cooled to the radiator. Finally, a closed-loop system cools only a single component, so if you want to liquid-cool a CPU and a video card, you need space for two systems.

Check your case for clearance before purchasing a closed-loop liquid cooling solution.

Installation Requires Expertise

A custom-built liquid cooling application requires a significant level of technical knowledge to install. Although you can buy a kit from a cooling manufacturer, you still must install it. Every case has a different layout, so you must cut and route the tubes precisely to fit your case. If you don't get all this right, you could damage your system.

Improper installation can cause leaks, which can damage internal components and pose a fire risk.

What Are the Alternatives?

Recently introduced closed-loop liquid cooling systems require no maintenance and are easy to install. They might not offer the performance of a custom-built system with larger liquid reserves and radiators, but there's almost no risk. Closed-loop systems still offer some performance benefits over air-cooled CPU heatsinks, though, including larger horizontal tower heatsinks and less space requirements.

Is There a Liquid-Cooled System in Your Future?

Air cooling is still the most common form of cooling because of the ease and cost of implementing them. However, as systems continue to shrink and demands for high-performance systems increase, liquid-cooling solutions are going to become more common in desktop computer systems.

Some companies are looking into the possibility of using liquid-cooling options for some high-performance laptop computer systems. As of now, though, liquid cooling is found only in the most extreme of performance systems that are custom-built by users and high-end techs.

  • How do you install liquid cooling?

    Install and secure the backplate, fans, radiator, and pump. Then connect all of the cables and power your system on. Finally, make sure everything is functioning properly and download and install any software that came with the cooling system.

  • How long does liquid cooling last?

    As long as you don't run into issues like a defective pump and take good care of your cooling system, you can generally expect to get at least five years out of it.

  • How can you tell if your liquid cooling is working?

    You can test your CPU's temperature; if it's overheating, that's a sure sign there's a problem. If the cooling pump is connected to the motherboard, you can go into BIOS and check its RPM. If the RPM is 0 or N/A, the cooling pump is not functioning.

  • How often should you change the liquid cooling in a PC?

    If you have an All-in-One (AIO) cooling system, or a Closed Loop cooler, you don't need to change the liquid in it. These are sealed systems and shouldn't be opened. For other cooling systems, the computer peripheral manufacturer Corsair recommends changing the fluids every 12 months to prevent build-up and ensure optimal performance.

  • How do you change the liquid cooling in a PC?

    Take the cooler out of your PC and drain it, replacing any old tubes as needed. You can use a big syringe to inject new coolant into the pump unit and reservoir. Connect the pump to the radiator, seal the tubes, and then test to ensure everything is functioning correctly.

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