Updated March 31, 2021 by Christopher Thomas

The 9 Best CPU Liquid Coolers

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This wiki has been updated 22 times since it was first published in February of 2016. Overclocking can make the most of a system, but it can also cause overheating, leading to compromised performance and potential damage. These closed-loop liquid coolers utilize fluid thermodynamics to remove excess heat from the CPU and expel it into the environment via a radiator and fans, helping maintain safe operating temperatures no matter how far you've pushed your processor. When users buy our independently chosen editorial choices, we may earn commissions to help fund the Wiki.

1. NZXT Kraken X63

2. Corsair H115i Elite Capellix

3. Corsair H115i Pro XT

Editor's Notes

March 30, 2021:

The only major difference this time around is the discontinuation of an older version of the EVGA CLC 120, which is outperformed by enough other options that its presence shouldn't be missed. To be clear, we did update a majority of the models here, but most have been replaced with very similar new versions, which are the ones we now recommend. Of course, it's important to remember that these things are routing liquids through expensive electronics, so it's absolutely imperative to get something you trust. For that reason, we stuck with the reputable brands and their very most recently refined models.

At the end of the day, though, if you're not perfectly comfortable with liquid cooling, there are plenty of high-quality air coolers available. In fact, in certain builds, an air cooler can work better than an AIO, although the all-in-ones are still ideal for small form factor PCs and anyone struggling with high case temperatures.

March 04, 2020:

I’ve taken some time to include some of the newer closed-loop systems with high thermal-removal efficiencies. The Corsair H60 is a nice single-fan cooler that’s great for processors for less demanding cooling applications, and outperforms many 120-mm and even 140-mm fans, though I obviously can’t compare its capabilities to larger multi-fan closed systems.

At the other extreme, if you’re really taxing or overclocking your CPU, and you have a graphics card or two for gaming or for bitcoin mining or whatever, then your best bet short of an open-loop system may be an AIO(All-In One) cooler with a larger radiator surface area like the Cooler Master ML360R.

The Corsair H115i Platinum is barely more expensive than the previously-listed Corsair Hydro – which should have really been called the Corsair H115i Pro. I thought of doing a direct replacement of the Platinum with the Pro, since the Platinum has slightly more powerful fans and is a little less noisy, and since the version of the Pro that was listed needed updating anyway to a newer version of the same model was released in 2020. I’ve decided instead to list the Platinum separately and also kept the Corsair H115i Pro XT, since both these systems are some of the best.

By extension, the list of best-performing systems is generally dominated by EVGA, Corsair and NZXT models with high RPM’s. For instance, both the dual-fan EVGA CLC 280-mm and 240-mm options perform very similarly in tests, but I decided to include the EVGA CLC 240, which is the 240-mm version comprised of two 120-mm fans. For reference, at around 2400 RPM, the CLC 240 kept the core of an Intel i7 processor at about 35 C above room temperature – or only a mere 2.1 C above what the CLC 280 maintained the temperature at. Remember, a CPU like an i7 can tolerate operating temperature of up to around 68 C.

I’ve also updated the NZXT Kraken X62 to the NZXT Kraken X63. The X62 was a very good model, but it was a little old, and the X63 is just as good. Now, a lot of people emphasize RGB lighting options as a valuable feature in AIO’s – I personally think that it's nothing more than a decorative feature and it doesn’t add much function to your cooler, but if you do value this feature a lot, then check out our RGB CPU Coolers.

4. Cooler Master ML360

5. EVGA CLC 240

6. Corsair H60i

7. Thermaltake Water 3.0

8. Arctic Liquid Freezer

9. Silverstone Tundra V2

Letting Your Computer Keep Its Cool

As transistors change their status, electricity is moved around the microchip.

If you're a programmer, engineer, graphic artist, or any computer professional who requires fast and powerful processors, you're likely to hear the sound of a whirring fan from within your machine. In many desktop and laptop situations, an internal fan is usually good enough to prevent overheating and to keep your computer's components cool with heavy use. However, if you use a lot of fancy hardware and you believe in constant upgrades to allow the machine to run faster than it did before, then you will need additional power to maintain those components and keep them cool. This extra power may generate more heat than your fans can handle on their own. In such situations, liquid cooling solutions will come in handy.

The process of computer cooling is defined as the removal of wasted heat produced by the machine's internal components in order to maintain their optimal operating temperatures. Those components most susceptible to overheating include the computer's central processing unit, graphics cards, and hard disk drives.

A computer's heat comes from its microchips and transistors. A microchip is a set of interconnected electronic components imprinted onto a small chip made from semiconducting material (e.g. silicon). These interconnected electronic components are sometimes referred to as integrated circuits. A transistor is an electrical switch that is either on or off at a given time. As transistors change their status, electricity is moved around the microchip. The more transistors a microchip has, and the faster they change their state, the hotter the microchip becomes. This is where the liquid cooling concept becomes important.

Water has a high degree of thermal conductivity, meaning that it can move heat faster than air can. Water also has a high specific heat capacity, meaning that it can absorb more heat than air does before it starts to feel hot. For that reason, if you have a powerful computer with components that produce more heat than the air around them is capable of absorbing, a liquid CPU cooler will be more effective at preventing overheats. Liquid cooling will also allow your machine to run quieter than it would using traditional fan technology.

Heat Up Your Search For Cooling Down

Also referred to as water cooling, liquid cooling for a computer works in a similar fashion to how a car's cooling system works. Although a car's heat is generated by the burning of fuel (internal combustion) and a computer's heat comes from its microchips and transistors, both leverage the process of thermodynamics whereby heat moves from warmer locations to cooler ones.

One may also be able to find companies that sell high-powered PCs with liquid cooling functionality already integrated into their systems.

A car's cooling system, for example, circulates water from the engine to the radiator. As the water approaches the radiator, that water's heat is drawn away, causing it to cool off as it heads back toward the engine. At the same time, the car's internal fan circulates air around the heated radiator. This air becomes warmer due to the radiator having expelled some of its own heat, ultimately cooling the radiator.

The components of a computer's liquid cooling system include a pump for moving coolant to the CPU, a radiator for dispelling heat, a fan for moving air over the radiator, a coolant reservoir that holds extra water, and a series of hoses that connect these parts together. The computer also uses a water block to cool the microchips. A water block is made of a heat-conductive metal (e.g. copper) and is filled with hollow tubes. Its flat metal bottom sits directly on top of the chip being cooled. Thermal paste (also known as thermal grease) is often sandwiched between the microchip and water block in order to improve heat transfer between both surfaces.

If the idea of searching for individual components for a liquid cooler doesn't appeal to you, ready-to-use cooling kits are certainly available on the market as well. These self-contained coolers will plug into your computer's expansion slots or power supply to provide cooling to a specific type of microchip. The kits also come with instructions for assembly. One may also be able to find companies that sell high-powered PCs with liquid cooling functionality already integrated into their systems.

Quiet operation is another key feature to look for in a CPU liquid cooling system, since the main point of the investment is to allow your computer to run more efficiently and quieter than it would with the use of its internal fans alone.

Some coolers also have variable speed settings for their pumps, which can be useful as the degree of processing power for a given task can fluctuate over time.

A Brief History Of CPU Liquid Coolers

The process of cooling hot computer components dates as far back as the early 1980s with the use of Fluorinert to cool the Cray-2 supercomputer. The popularity of water cooling powerful computer systems increased throughout the 1990s with most coolers being homemade during that decade. Many were constructed with car radiators, aquarium pumps, homemade water blocks, PVC and silicone tubing, and reservoirs using plastic bottles. It wasn't until Advanced Micro Devices released its Athlon processor in 2,000 that home-based liquid coolers became prevalent.

By 2011, custom computer retailers were manufacturing water-cooling components compact enough to fit inside most computer cases. The Apple Power Mac G5 was the first mainstream desktop computer to offer fully-integrated water cooling as a standard. This was quickly followed by Dell with their XPS machines leveraging thermoelectric cooling principles. As the CPU has become more powerful over time, the popularity of liquid cooling has continued to grow, though it is still a relatively small market.

Christopher Thomas
Last updated on March 31, 2021 by Christopher Thomas

Building PCs, remodeling, and cooking since he was young, quasi-renowned trumpeter Christopher Thomas traveled the USA performing at and organizing shows from an early age. His work experiences led him to open a catering company, eventually becoming a sous chef in several fine LA restaurants. He enjoys all sorts of barely necessary gadgets, specialty computing, cutting-edge video games, and modern social policy. He has given talks on debunking pseudoscience, the Dunning-Kruger effect, culinary technique, and traveling. After two decades of product and market research, Chris has a keen sense of what people want to know and how to explain it clearly. He delights in parsing complex subjects for anyone who will listen -- because teaching is the best way to ensure that you understand things yourself.

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