The best AIO cooler – the top liquid coolers for your CPU in 2021

The best AIO cooler is one that should make the perfect combination with some of the best gaming CPUs. Despite increases in performance-to-TDP ratios, processors can still get mighty hot these days – especially if you overclock them. If you’ve learnt how to overclock your CPU and want to put these skills to the test, you might have an easier time of it using one of the best liquid coolers over an air cooler. As more and more graphically intensive titles like Metro Exodus are released, overclocking might become more common. A good AIO cooler lets you overclock to crank out more performance with less risk of melting your CPU to a crisp.

The top cooling manufacturers have been put to the test on our test bench, with all-in-one (AIO) liquid CPU coolers from Cooler Master, NZXT and Corsair. But why do you need to go all out on a CPU cooler? If you want to push your processor’s clock speeds to meet its potential then you need to make sure overheating isn’t a factor, and that’s where liquid coolers come in.

You might think water shouldn’t mix with electronics, yet an effective pump and radiator combo will move heat away from that CPU faster than you can say ‘thermal throttling’. (That, and the liquid is usually a mixture of water and other coolants). Of course, they often feature more RGB LEDs than you can shake a stick at, so you need not worry about colour-matching with the rest of your rig.

All-in-one liquid coolers take all the pain out of putting the soggy stuff inside your PC. You can create your own custom loops, letting you keep the best graphics cards running cool too, but that’s far more in-depth and a serious build project in its own right.

AIO coolers, however, can be set up in half an hour and still make a tangible difference to your gaming PC.

Here are the best AIO coolers:

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nzxt kraken x63

The best AIO cooler is the NZXT Kraken X63.

This 280mm liquid cooler from NZXT is our pick if you’re looking for a seriously good all-rounder. The virtually silent fans on the radiator have fluid-dynamic bearings, giving them a longer lifespan and quieter operation than any other fan technology. Naturally, there’s customisable RGB lighting on the pump cover so people know you’re not running any old stock solution.

With the X63 you’ll see idle and load temps in another league to air coolers. If you are overclocking, just make sure you’re picking up one of the best gaming motherboards to match.

What we like…
 Great thermal performance
Affordable
Near silent fans

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nzxt kraken m22

The best 120mm AIO cooler is the NZXT Kraken M22.

It’s true that the bigger the radiator, the better the job an AIO cooler can do, but sometimes you just don’t have the space for one. This doesn’t mean you should sacrifice the chilling effects a liquid cooler offers, however, as there are smaller options to choose from that might be easier to shimmy into your case, still offering cooling a cut above the best CPU coolers.

The NZXT Kraken M22 is the little brother to our favourite AIO cooler and comes with many of the same perks. It keeps things quiet, goes easy on your wallet, and keeps your CPU at the right temperature for gaming, but best of all, it could be considered the most compatible AIO cooler you’ll find with its small form factor and support for all modern Intel and AMD CPUs.

What we like…
 Compact
Wide range of compatibility
Quiet fans

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Corsair H100i Pro RGB

The quietest AIO cooler is the Corsair H100I Pro RGB.

The latest update to the classic Corsair H100i liquid CPU cooler isn’t just about that new ring of LED light around the shrunken pump. It’s not even about the slicker radiator design, either. No, the best thing about the new H100i Pro RGB is the noise it makes… or rather the lack of noise, making it perfect for a near silent gaming PC build.

Thanks to the super-quiet maglev fans included in the package, and the addition of a Zero RPM mode, the Pro RGB can stay almost entirely silent for most of the time your PC’s online. Relying on the flow of water and the passive cooling of the radiator alone, the H100i can keep the CPU cool enough not to have to worry the fans until you start to really thrash it. That means in a lot of the best PC games, ones that are more GPU and less CPU dependent, you may not hear the fans at all.

What we like…
 Near-silent
 Maglev fans
 Good software

Read the PCGamesN Corsair H100i Pro RGB review for our full verdict and score.

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cooler master masterliquid ml360r

The best RGB AIO cooler is the Cooler Master MasterLiquid ML360R.

There’s no reason you can’t be serious about your cooling and want to add a splash of colour to your gaming PC in the process – after all, the best gaming keyboards and best gaming headsets all have RGB nowadays, so why shouldn’t your CPU cooler match?

Cooler Master’s MasterLiquid series does this beautifully with its bright CPU block, and it comes in a handful of different sizes to make your next CPU upgrade a bit easier. The MasterLiquid ML360R has plenty of sufrace area and three 120mm fans to dissipate heat across its large radiator.

What we like…
Colourful RGB
Three fans!
Remains affordable

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Cooler Master MasterLiquid ML240L

The best cheap AIO cooler is the Cooler Master MasterLiquid ML240L.

If you’re looking for a cost-effective AIO cooler that still looks brilliant in your windowed case, then this 240mm liquid cooler from Cooler Master is a great option. There’s customisable RGB lighting on both the fans and the pump cover.

Even at this price point, it’s still better than pretty much any air cooler you’re going to find – plus, it still looks cool, right?

What we like…
That low price
RGB everywhere
Two 140mm fans

How to keep your gaming PC cool

Here’s our handy video guide on how to keep your gaming PC cool. PCGamesN also has a full guide on how to keep your gaming PC cool.

AIO cooler buying guide

Sure, going to the extreme effort of adding a full water cooling loop to your gaming rig will give you the best combination of performance and pretties, but it takes a hell of a lot of work. And if you’re not building a showpiece machine, or a super-overclocker, then chances are you just want something simple to chill your chips with.

And that’s the beauty of the all-in-one liquid cooler. The NZXT Kraken X63 is our current favourite AIO cooler, with great thermal performance and near-silent operation, plus a sleek design which will look at home in even the best gaming PC build.

Corsair also have some similarly brilliant liquid coolers on offer, and its H100i Pro RGB is the best for a PC that you want to be seen and not heard, with fans deactivating under light load for almost pure silence.

Then at the more budget end of the market, the Cooler Master’s MasterLiquid ML240L is the cheapest AIO cooler on our list, yet still provides a 240mm radiator and that all-essential RGB lighting. Now there’s no excuse not to liquid chill your chips.

AIO cooler price list