Best PC Case for a 420 mm AIO in 2026: Lian Li Lancool III, Fractal North XL, Meshify 2 XL or Corsair 7000D, Which One for Your Liquid Freezer III 420?

A 420 mm AIO is a radiator built for three 140 mm fans. The ARCTIC Liquid Freezer III Pro 420 measures 458 × 138 × 38 mm according to ARCTIC. Having three 140 mm fan mounts is therefore not enough: the case must state 420 mm radiator compatibility in black and white, and at a specific location (front, top, side or bottom).

In short: the Lian Li Lancool III is the best choice for most builds: a mid tower with 420 mm support at the front and top, and room for a 435 mm graphics card. The Fractal Design North XL is the design pick, but its 420 mm radiator only fits at the front. For a very large build or a custom loop, the Corsair 7000D AIRFLOW and the Fractal Meshify 2 XL / Define 7 XL take two 420 mm radiators at the same time.

Every figure in this guide comes from the manufacturers’ spec sheets. We left out cases whose 420 mm compatibility is not confirmed by the manufacturer, such as the Phanteks NV7, which is limited to 360 mm. For the basics, also read our gaming PC case guide and our guide to the watercooled gaming PC.

Click to enlarge

• The “420 mm” mention at the location you want. Many cases accept a 420 mm radiator at the front but only 360 mm at the top (North XL, Eclipse G500A), or the other way round (O11 Dynamic EVO XL, NV9 MKII).
• The real length of the radiator. Count on about 458 mm for a Liquid Freezer III Pro 420, which is well above the 420 mm in the name. The case spec sheet sometimes gives the maximum accepted length: 475 mm at the front of the Eclipse G500A, 515 mm at the top of the NV9 MKII.
• The total thickness at the top, radiator plus fans. On the Lancool III, Lian Li limits the whole assembly to 75 mm at the top and asks for RAM modules of 44 mm maximum with a 420 mm radiator up there.
• The remaining graphics card length. A front radiator eats into the space ahead of the graphics card: Fractal states 413 mm on the North XL, but 380 mm with a front radiator. Check the length of your graphics card, especially with an RTX 5090 (see our guide which PC case for an RTX 5090).
• The position of the tubes. At the front, preferably place the pump lower than the top of the radiator, with the tubes pointing down, so that air does not collect in the pump.

Mounted at the front as intake, the radiator receives fresh air: the processor is cooled better, but the air entering the case is slightly warmed for the graphics card. It is the only possible choice on the North XL, the Torrent and the Eclipse G500A.

At the top as exhaust, the radiator pushes the CPU heat straight out of the case and leaves the front to the intake fans. It is often the best compromise with a very hot graphics card. Then check the RAM height and the maximum thickness stated.

In both cases, keep good intake fans: our selection of the best PC case fans will help you complete the airflow.

Click to enlarge

The Lancool III is the easiest case to recommend for a 420 mm radiator. Lian Li states a 360 or 420 mm radiator at the front and top, plus a 360 mm one above the power supply cover. It takes graphics cards up to 435 mm, CPU coolers up to 187 mm and E-ATX motherboards under 280 mm wide.

It comes with four 140 mm fans (three at the front, one at the rear), mesh panels on the front, top and bottom, and hinged glass panels. For a 420 mm radiator at the top, Lian Li asks you to remove the rear fan, keep the tubes towards the rear and stay under 75 mm of total thickness. At the front, the bracket must be mounted in its first position.

Click to enlarge

The North XL takes the look of the North with its walnut front, but bigger. Fractal states a radiator of up to 420 mm at the front and 360 mm maximum at the top. It takes E-ATX motherboards, 185 mm CPU coolers and 413 mm graphics cards, or 380 mm with a front radiator.

Three Aspect 14 PWM fans are supplied at the front. It is the right choice if your PC sits in a living room and your graphics card does not exceed 380 mm. If you want your 420 mm radiator at the top, get the Lancool III instead.

The 7000D AIRFLOW is a full tower of more than 80 litres. Corsair states two simultaneous 420 mm radiators (top and front), up to three 360 mm ones, and even a 480 mm one on the side. It takes graphics cards up to 450 mm and CPU coolers up to 190 mm, with three 140 mm fans supplied. The only constraint: its 60 cm height.

The Meshify 2 XL takes a radiator of up to 420 mm at the front and top, 280 mm at the bottom, with a graphics card of up to 530 mm according to Fractal. Its mesh front and three Dynamic X2 GP-14 fans make it the airflow version of Fractal’s full tower.

The Define 7 XL has the same usable dimensions as the Meshify 2 XL, with a solid front and sound-dampening foam. Fractal states 420 and even 480 mm at the front and top. For a 420 AIO at the top, replace the solid top panel with the ventilated panel supplied. It is the quiet choice, at the cost of weaker airflow.

The O11 Dynamic EVO XL has no ventilated front: it is a showcase. Lian Li states a 420 mm radiator at the top, on the side and at the bottom, up to three 420 mm at once, with 460 mm of graphics card length. The CPU cooler is limited to 167 mm, and the case is sold without fans: include them in your budget.

The NV9 MKII pushes the concept even further: 420 mm at the top and bottom, 420 or 480 mm on the side, up to three 420 mm radiators plus a 280 mm one at the rear according to Phanteks. The graphics card can reach 490 mm and the CPU cooler 205 mm. There is no front radiator, since the front is glass.

The Torrent is one of the best-ventilated cases on the market, with five fans supplied (two 180 mm, three 140 mm). Fractal states a 420 mm radiator at the front and bottom, but no radiator at the top. The graphics card can be up to 461 mm. Pick it if you accept the 420 mm radiator at the front, in place of the 180 mm fans.

The Eclipse G500A is a more classic airflow mid tower, with a fine mesh front and top. Phanteks states a 420 mm radiator at the front (142 × 475 mm area), but only 360 mm at the top. It takes a 435 mm graphics card and a 185 mm CPU cooler.

The ARCTIC Liquid Freezer III Pro 420 is the reference in this category: a 458 × 138 × 38 mm radiator and three 140 mm fans. The Liquid Freezer III 420 A-RGB is the older version, with lighting. To compare AIOs in 240, 280 and 360 mm, see our comparison of the best AIOs. And if an AIO seems excessive, a good tower air cooler remains an option: our guide to choosing a CPU cooler will help.

• Believing that three 140 mm mounts are enough: the radiator is about 458 mm long.
• Taking a North XL or an Eclipse G500A for a 420 mm radiator at the top: they are limited to 360 mm up there.
• Forgetting the total thickness of radiator plus fans at the top, and the RAM height.
• Forgetting the graphics card: a front radiator reduces the available length.
• Leaving the pump at the highest point of the loop.

Yes, in some: the Lancool III takes it at the front and top, the North XL, the Torrent and the Eclipse G500A at the front only. Always check the manufacturer’s spec sheet.

A 420 mm radiator has more surface, which lets the fans spin slower at the same temperature. A 360 mm one remains enough for most gaming processors and fits in many more cases.

Yes on showcase cases like the Lian Li O11 Dynamic EVO XL and the Phanteks NV9 MKII, and a 480 mm one on the Corsair 7000D AIRFLOW.

For most builds, get the Lian Li Lancool III, which takes the 420 mm radiator at the front and top. If you want an elegant PC and a 420 mm radiator at the front suits you, the Fractal North XL is perfect. For two 420 mm radiators, aim for the Corsair 7000D AIRFLOW or the Fractal Meshify 2 XL / Define 7 XL. For a showcase, the O11 Dynamic EVO XL or the NV9 MKII. Airflow alternative in a mid tower: the Eclipse G500A, at the front only.