How to Choose a Case for Liquid Cooling

What to look for in a liquid cooling case

A case for liquid cooling needs to fit the radiator and fans of your cooler, not just the motherboard and graphics card. The three numbers on a case spec sheet that matter most are the supported radiator sizes, the mounting positions, and the clearance for radiator thickness. For an overview of case sizes, see the guide on case sizes.

Radiator sizes are named by the fan size and the number of fans. A 120mm radiator fits one 120mm fan, a 240mm radiator fits two, a 360mm radiator fits three, and a 420mm radiator fits three 140mm fans. The case must list that exact size as supported in a specific location, such as "360mm radiator in front" or "280mm radiator in top."

The thickness of the radiator also matters. Most all-in-one liquid coolers use a radiator around 27mm thick, but some use thicker ones. The case must have enough clearance between the radiator and the motherboard, the graphics card, or the top panel. A spec sheet may list a maximum radiator thickness, or you can measure the space yourself.

Fan compatibility is usually listed as the number of fan mounts and the sizes they accept, such as three 120mm or two 140mm. A radiator mount can often accept either size, but not always. Check the case's fan support table to see which sizes fit in the top and front.

For a broader look at how a case fits into a gaming PC build, see the air cooling versus AIO comparison to understand the differences between cooler types.

Radiator sizes and what they mean

The radiator size determines how much cooling surface the liquid passes through. A larger radiator has more surface area, which allows the coolant to shed heat more effectively. The trade-off is that a larger radiator needs more space inside the case.

Common radiator sizes are 120mm, 140mm, 240mm, 280mm, 360mm, and 420mm. The number refers to the length of the radiator in millimeters, which corresponds to the number of fans it can hold. A 240mm radiator holds two 120mm fans, a 280mm holds two 140mm fans, and a 360mm holds three 120mm fans.

The most popular size for high-performance gaming PCs is 360mm, because it fits in most mid-tower cases and provides ample cooling surface. A 280mm radiator is a good alternative when a case does not support 360mm, and it can be quieter because 140mm fans move more air at lower speeds.

The case spec sheet will list which radiator sizes it supports in each location. For example, a case might support a 360mm radiator in the front but only a 280mm in the top. Always match the radiator size to the case's supported list. For a direct comparison of 360mm and 280mm radiators, see the 360mm versus 280mm AIO comparison.

For a comparison of 240mm versus 360mm all-in-one coolers, see the 240mm versus 360mm AIO comparison.

Top mount versus front mount

The two main places to mount a radiator are the top and the front of the case. Each has advantages and trade-offs.

A top mount is common because it uses the space above the motherboard, which is often free. It allows the radiator to exhaust hot air upward, which works with the natural tendency of heat to rise. However, a top mount can conflict with tall RAM heatsinks or a large CPU cooler, and the case must have enough clearance between the top panel and the motherboard.

A front mount pulls cool air from the front of the case through the radiator and into the system. This can provide cooler air to the radiator, but it also means the air that reaches the graphics card and other components has already been warmed by the radiator. Some cases allow a front mount with the fans on the outside of the radiator to reduce this effect.

Some cases support both top and front mounts, giving you the flexibility to choose based on your other components. If you have a long graphics card, a front mount might not leave enough room, so a top mount is safer. If you have tall RAM, a top mount might be tight, so a front mount is better.

The choice also affects the overall airflow direction. A top mount with exhaust fans creates a negative pressure setup, while a front mount with intake fans creates positive pressure. Both can work well, but the case's fan configuration should be balanced.

For more on airflow and fan placement, see the guide on how many case fans a gaming PC needs.

Thickness clearance for radiator and fans

The thickness of the radiator plus the fans is a key measurement. A typical radiator is about 27mm thick, and a standard 25mm fan adds another 25mm, for a total of about 52mm. Some radiators are thicker, up to 45mm or more, and some fans are thinner, but the total is what matters.

The case must have enough clearance for that total thickness in the chosen mount location. For a top mount, the clearance is between the top panel and the motherboard or RAM. For a front mount, the clearance is between the front panel and the graphics card or the drive cages.

A case spec sheet may list a maximum radiator thickness, such as "up to 55mm in front" or "up to 45mm in top." If not, you can measure the space with a ruler. The clearance is especially important in compact cases, where a thick radiator can block other components.

When you choose a case, compare the radiator thickness of your cooler to the case's clearance. If the case does not list a thickness limit, look at the distance between the motherboard tray and the top panel, or between the front panel and the GPU mounting area.

For a guide on choosing a CPU cooler for RAM clearance, see the guide on CPU cooler for RAM clearance.

Fan compatibility with radiator mounts

Radiator mounts are designed for specific fan sizes. A 120mm radiator uses 120mm fans, and a 140mm radiator uses 140mm fans. Some mounts can accept both, but the case spec sheet will state which sizes are supported.

The number of fan mounts in a case is usually higher than the number of radiator mounts. For example, a case might have three 120mm fan mounts in the front, but only two of them can hold a radiator because the third is blocked by a drive cage. The radiator support list is separate from the fan support list.

Fan thickness also matters. Most fans are 25mm thick, but some high-static-pressure fans are 30mm or more. The radiator thickness clearance must include the fan thickness, so a thick fan can reduce the available radiator thickness.

When you plan a build, decide on the radiator size first, then check the case's fan support for that location. If the case supports a 360mm radiator in the front, it will have three 120mm fan mounts there, but the radiator thickness clearance might be less than with a 280mm radiator.

For a comparison of 120mm versus 140mm case fans, see the 120mm versus 140mm case fan comparison.

Other case features that affect liquid cooling

Beyond radiator support, a few other case features can make liquid cooling easier. A removable top panel or front panel can simplify installation, because you can mount the radiator and fans before sliding the assembly into place.

Cable management space is important because liquid cooling adds tubes and a pump block that need routing. A case with a deep cable management channel behind the motherboard tray gives you room to hide the tubes and keep airflow clear. For a guide on choosing a case for cable management, see the cable management case guide.

The pump and reservoir of an all-in-one cooler are usually mounted on the CPU, so the case does not need a separate pump mount. But if you plan a custom loop, you will need space for a reservoir and pump, which is a different consideration.

The graphics card length can also affect radiator placement. A long GPU can block a front-mounted radiator, so check the maximum GPU length in the case spec sheet and compare it to your card.

For a guide on choosing a case for airflow, see the airflow case guide.

What to pick for your build

For a high-performance gaming PC with a 360mm all-in-one cooler, choose a mid-tower case that lists 360mm radiator support in the top or front. Make sure the case has enough clearance for the radiator and fans, and that the GPU length does not conflict with a front mount.

For a more compact build with a 240mm or 280mm cooler, a smaller mid-tower or even a mini-ITX case can work, but check the radiator support carefully. Some small cases only support 240mm in the front, not the top.

If you plan to use a 420mm radiator, you will need a full-tower case, because 420mm radiators are long and require a large case. Full-tower cases also offer more room for custom loops and multiple radiators.

The choice between top and front mount depends on your other components. If you have tall RAM, a front mount is often easier. If you have a long graphics card, a top mount is safer. Both work well, so prioritize the clearance that fits your parts.

For a list of prebuilt gaming PCs that come with liquid cooling, see the best prebuilt gaming PC guide. That guide covers systems with all-in-one coolers already installed.

What to pick for your play

Questions

What radiator sizes should a case support for liquid cooling?

The most common sizes are 120mm, 140mm, 240mm, 280mm, 360mm, and 420mm. A 360mm radiator is a popular choice for high-performance builds, while 240mm and 280mm are common for compact systems. The case spec sheet lists which sizes it supports.

Is a top mount or front mount better for a radiator?

Both work well. A top mount exhausts hot air upward and avoids conflicts with long graphics cards, but it can be tight with tall RAM. A front mount pulls cool air through the radiator, but it can warm the air that reaches other components. Choose based on your component clearances.

How much thickness clearance do I need for a radiator and fans?

A typical radiator is about 27mm thick, and a standard fan is 25mm thick, so you need about 52mm of clearance. Some radiators are thicker, so check the case's maximum radiator thickness and measure the space if needed.

Can I use 140mm fans on a 280mm radiator?

Yes, a 280mm radiator is designed for two 140mm fans. The case must support 140mm fans in that mount location. Some mounts accept both 120mm and 140mm fans, but the radiator size determines the fan size.

Do all cases support 360mm radiators?

No. Many mid-tower cases support 360mm radiators, but some smaller cases only support 240mm or 280mm. Full-tower cases are more likely to support 360mm or 420mm. Always check the case's radiator support list.

What other case features matter for liquid cooling?

Removable panels for easy installation, cable management space for tubes, and GPU length clearance are important. A long graphics card can block a front-mounted radiator, so check the maximum GPU length.