420mm AIO CPU Coolers represent the pinnacle of AIO liquid cooling technology, offering unprecedented performance. Of course, the perceived performance of 420mm coolers alone is not enough to blindly pick any option without any prior research. It is imperative to weigh every aspect of a cooler to get an option that caters to your personal requirements. That is why I have tested a bunch of different 420mm AIOs to round up the top options.
Take a look at my selection of the best 420mm AIO, all compared with each other:
Last Updated:
- April 23, 2024: Some formatting changes to improve readability. I’ve also included benchmarks of my selections from their individual reviews.
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Best 420mm AIO CPU Coolers
Here are the 420mm AIO CPU Coolers I would recommend:
- Best Overall: Alphacool Eisbaer Aurora 420
- Best Performance: CORSAIR iCUE H170i Elite LCD XT
- Best Value: ARCTIC Liquid Freezer II 420
- Best Looking: Silverstone IceMyst 420
Alphacool Eisbaer Aurora 420
Best Overall 420mm AIO CPU Cooler
Cooler Type: 420mm AIO Liquid Cooler | Radiator Dimensions (LxWxH): 458 × 144 × 30 mm | Fans: 3x 140mm Fans | Fan Speed: 1500 RPM | Noise Level: – | Socket Support: Intel LGA 2066, 2011-v3, 2011, 1700, 1200, 1151, 1150, 1155, AM2, AM2+, AM3, AM3+, FM1, FM2, FM2+, AM4 | RGB: Yes
Pros
- Beastly cooling performance
- Copper radiator
- Reduced noise levels
Cons
- Inconvenient installation
The Alphacool Eisbaer Aurora 420 is equipped with three AURORO LUX Pro 140mm fans that are capable of reaching a maximum fan speed of 1500 RPM. Moreover, Alphacool has made use of its DC-LT2 pump, which provides a maximum operational speed of 2600 RPM. We tested both Ryzen 9 7950X and Core i7-13700K, and the AIO kept these high-end CPUs at 84°C and 85°C, respectively, after a full 30-minute Cinebench R23.2 run.
Build quality on the Alphacool Eisbaer Aurora 420 is nothing short of remarkable. It comprises a metallic housing for the radiator, a copper fin stack, and a total of 12 channels designated for coolant flow. Aesthetically, the Eisbaer Aurora 420 is not vastly different from its predecessors. You get a similar-sized pump reservoir combination along with RGB lighting on top. It is worth mentioning that lighting can be controlled using the included controller or third-party software.
When our very own editor-in-chief, Sajjad Hussain, tested the Alphacool Eisbaer Pro AURORA 420, here’s what he said:
Their Eisbaer Pro AURORA 420 is an all-rounder liquid cooler capable of taming your high-end CPUs with the ability and capacity to handle overclocking as well. Plus, it comes with extensive socket support and an aura of digital RGB lighting effects.
Buy It If:
Here are a few shots we took of the Alphacool Eisbaer Aurora 420 during our testing:
✅You want the ideal 140mm cooler: Packed with powerful 140mm fans and Alphacool’s DCLT 2 pump, the Alphacool Eisbaer Aurora 420 provides impeccable cooling performance without compromising on build quality, appearance, or noise levels.
Don’t Buy It If:
❌You want convenient installation: Requiring 17 parts for the installation of the CPU block, setting up the cooler can be a hassle, especially for beginners.
What Makes It The Best Overall 420mm AIO CPU Cooler?
The Alphacool Eisbaer Aurora 420 comes with decently powerful AURORA LUX Pro fans, a capable pump, and robust build quality without costing an egregious amount. Adding on to that, the cooler also does not disappoint when it comes to aesthetics, making it the Best Overall 420mm CPU Cooler.
- Read Our ALPHACOOL Eisbaer Pro AURORA 420 Review
- Read Our ALPHACOOL Eisbaer Pro AURORA 360 Review
- Read Our ALPHACOOL Eisbaer Pro AURORA 280 Review
- Read Our ALPHACOOL Eisbaer Pro AURORA 240 Review
| Performance: 9/10 | Value: 8/10 |
| Features: 7/10 | Design: 8/10 |
CORSAIR iCUE H170i Elite LCD XT
Best Performance 420mm AIO CPU Cooler
Cooler Type: 420mm AIO Liquid Cooler | Dimensions (LxWxH): 457 × 137 × 53 mm | Fans: 3x 140mm Fans | Fan Speed: 1700 RPM | Noise Level: 33.8 dBA | Socket Support: LGA 1700, 1200, 1150, 1151, 1156, 2011, 2066, AM4, AM5, sTR4 | RGB: Yes
Pros
- Top-notch cooling performance
- LCD Screen
Cons
- Expensive
420mm coolers are heralded for their beastly performance; however, the Corsair iCUE H170i Elite LCD XT takes that up a notch with its dense radiator and powerful AF140 Elite RGB fans. Speaking of which, the fans offer a maximum speed of 1700 while also peaking in at an airflow of 89 CFM. No wonder this beast kept the 13700K at 84°C after a full stress test in our in-house testing.
Weighing in at a whopping 1.95 kilograms, the Corsair iCUE H170i Elite is undoubtedly a monolithic cooler, which is precisely why it has been backed up by a solid structure. It uses an aluminum construction for the radiator, low permeation rubber for the tubing, and a copper CPU plate. Between clean-looking A-RGB on the fans all the way to the 480×480 LCD screen, the level of customizability the cooler offers is fantastic. That is further enhanced thanks to the clean black coating on the radiator, which blends well with all of the lighting on display.
Here’s what Nauman Siddique, our CPU cooling expert, had to say after testing the CORSAIR iCUE H170i Elite LCD XT:
With excellent thermal performance that is augmented by a well-executed IPS LCD Screen and extensive customization options using iCUE and lighting effects, the iCUE H170i Elite LCD XT is definitely a worthy contender should your wallet afford it in addition to your PC Case.
Buy It If:
Take a look at the Corsair iCUE H170i Elite LCD XT from our testing:
✅You want the best possible performance: The Corsair iCUE H170i Elite LCD XT ranks among the most powerful 420mm coolers you can your hands on.
✅You want a functional LCD screen: Its position as an enthusiast-grade AIO CPU cooler means the presence of an LCD screen is anything but extraordinary.
Don’t Buy It If:
❌You are on a limited budget: Coming in at a premium price tag, the Corsair iCUE h170i Elite LCD XT will be out of the question for anyone working with a limited budget.
What Makes It The Best Performance 420mm AIO CPU Cooler?
The Corsair iCUE H170i Elite LCD XT comes with powerful fans, a zero RPM mode, and an LCD screen for added customizability. Above all, it provides unparalleled cooling performance, taking the spot as the Best Performance 420mm CPU Cooler.
| Performance: 10/10 | Value: 8/10 |
| Features: 7/10 | Design: 8/10 |
Arctic Liquid Freezer II 420
Best Value 420mm AIO CPU Cooler
Cooler Type: 420mm AIO Liquid Cooler | Dimensions (LxWxH): 458 × 140 × 63 mm | Fans: 3x 140mm Fans | Fan Speed: 1700 RPM | Noise Level: – | Socket Support: LGA 1700, 1200, 115X, 2011-3, 2066, AM3(+), AM4, AM5 | RGB: No
Pros
- Phenomenal cooling performance
- Lower noise levels
- Enlarged radiator
- Fantastic Value
- VRM fan
Cons
- Plain looks
Much like the previous iterations in the Liquid Freezer series, the 420mm does not disappoint in terms of cooling performance. The P14 fans reach a maximum speed of 1700 RPM, which falls slightly behind the maximum operational speed of the pump, which stands at 2000 RPM. The AIO comes with fiber-reinforced tubing while also incorporating built-in cable management to hide any cables running through. In short, you get top-notch performance, and I was simply blown away by how well it handles high-end CPUs without breaking a sweat.
As for looks, the cooler comes encapsulated in a matte-black coating, which extends all the way to the P14 fans. Similarly, the water block also does not have any RGB or LCD, although its size is fairly large due to the presence of an additional VRM fan. It is worth mentioning that separate variants of the cooler do come with A-RGB fans for a little extra.
Praising the Liquid Freezer II’s exceptional noise performance, here’s what Nauman Siddique said in his review:
The ARCTIC Liquid Freezer – II 420 is a powerful cooler in the market that comes with a 6-year manufacturer’s warranty and offers fantastic thermal performance at almost silence, which is unheard of.
Buy It If:
Here are some of our shots when we tested the Arctic Liquid Freezer II – 420:
✅You need the best value possible: The Arctic Liquid Freezer II 420’s value supersedes that of any other 420mm cooler in the market, that too by a considerable margin.
Don’t Buy It If:
❌You need fancier aesthetics: The Arctic Liquid Freezer II 420 does not necessarily excel on the basis of visuals.
What Makes It The Best Value 420mm AIO CPU Cooler?
Not only does Arctic Liquid Freezer II 420’s performance benefit from the larger 37mm radiator, but it also blows every 420mm AIO out of the water when it comes to sheer value. Combine that with the addition of an integrated VRM fan, an efficient in-house pump, and high-performance P14 fans, and you get the Best Value 420mm AIO CPU Cooler.
| Performance: 9/10 | Value: 10/10 |
| Features: 7/10 | Design: 7/10 |
Silverstone IceMyst 420
Best Looking 420mm AIO CPU Cooler
Cooler Type: 420mm AIO Liquid Cooler | Radiator Dimensions (LxWxH): 456 × 120 × 28 mm | Fans: 3x 140mm Fans | Fan Speed: 1750 RPM | Noise Level: 30.8 dBA | Socket Support: LGA 1700, 1200, 115X, 2011, 2066, AM4, AM5 | RGB: Yes
Pros
- Great performance
- Aesthetically pleasing design
- Stackable fans
Cons
- Average noise output
IceMyst has gone to extraordinary lengths to maximize the cooler’s performance. The 140mm fans it arrives with offer a maximum speed of 1750 RPM. Perhaps the biggest peculiarity the series brings is the ability to stack fans on top of the pump to cool down separate parts of the motherboard. Everything ranging from VRMs, SSDs, and RAM modules can be cooled down using these fans. As a result, not only my 13700K was kept under optimal temperatures, but my board’s VRM temps also saw a marginal decrease during stress testing.
Tou get an aluminum radiator optimized specifically for higher pressures along with a convexed copper baseplate in order to maintain better contact with the CPU. While the pump doubles down as a mount for the stackable fans, its original functionality is also utilized through the three-phase, six-pole design in order to increase its overall reliability and efficiency.
On an aesthetic level, the Silverstone IceMyst 420 outdoes most coolers it competes against. Not only is the design remarkably uncluttered, but Silverstone has managed to sneak in clean RGB elements on the pump as well as the fans. This is further evidenced by their clean cable management system, which allows you to synchronize RGB through a single header for all of the fans.
Buy It If:
✅You are looking for a visually appealing 420mm cooler: From the silver finish on the pump to the neat RGB, the IceMyst 420’s design is certainly visually striking.
✅You intend to cool other components: Adding fans on top of the pump housing allows you to cool other components on the motherboard, which might be ideal for a motherboard that lacks onboard cooling.
Don’t Buy It If:
❌You want a silent experience: While the Silverstone ICeMyst 420 is reasonably quiet, its noise levels can be a problem for anyone who likes a quieter environment, especially if you add more fans to cool other components.
What Makes It The Best Looking 420mm AIO CPU Cooler?
Packed with an efficient motor consisting of a three-pole, six-phase design, and great value, the Silverstone IceMyst 420 does not miss the mark when it comes to integral components. It also does not fall behind in terms of build quality, all the while incorporating the novelty of stack fans. All of that is topped off with the cooler’s sleek visual appearance, which gives it the title of the Best Looking 420mm CPU Cooler.
| Performance: 9/10 | Value: 8/10 |
| Features: 9/10 | Design: 10/10 |
Thermal Performance Results
I’ve also tested my recommended 420mm AIO on the i7-13700K. Take a look at their results:
Important CPU Cooler Key Terms
It is easy to be inundated by the number of technical terms usually thrown in by manufacturers. Here are brief definitions of a few CPU Cooler key terms for anyone unaware of technical terms within the space.
- TDP: The thermal design power of a CPU cooler is a direct measure of its overall cooling capacity, determining the amount of heat it can dissipate.
- Liquid Cooling: Use of a liquid coolant to dissipate heat from computer components, namely the CPU in the case of an AIO cooler.
- Radiator: A radiator’s job is to dissipate the heat flowing into it into the surroundings. This is done through a combination of metal fins and fans.
- Pump: The pump serves the purpose of transferring the liquid to the radiator, where the heat can be dissipated.
- Thermal Paste: Thermal compound is a conductive material used to eliminate gaps between two surfaces and improve heat transfer.
- Noise Level: As suggested by the name, the noise output refers to the amount of noise generated from your AIO liquid cooler.
How We Selected The Best 420mm AIO CPU Coolers
There are a lot of factors you need to account for when selecting a CPU cooler. Here are a few factors I took into consideration when rounding up my top 420mm AIOs.
- Cooling Performance: Cooling performance is undoubtedly the most crucial aspect of a CPU cooler. Of course, the kind of performance you require will depend on the processor you are using. To put into perspective, a flagship processor will require a top-of-the-line cooler, especially if you intend on overclocking it. Components affecting AIO coolers’ cooling performance include the fans, radiator, and pump. Every cooler featured on my list performs well, facing no issues accommodating high-end processors.
- Acoustic Performance: A significant concern for triple-fan radiators can be the loud noise generated by the constant operation of the fans and the pump. In order to avoid this, you’ll need a cooler that remains quiet even under load. Thankfully, my list features several AIO CPU coolers that remain silent.
- Build Quality: A well-built cooler is the key to a sustainable computer system, which is precisely why you must opt for a cooler that does not compromise on its build quality. Ideally, an AIO cooler should consist of a well-constructed radiator, an efficient pump, as well as a solid fan that provides heat dissipation.
- Aesthetics: While aesthetics might not be the main concern for some, anyone interested in enhancing the look of their setup will need to purchase a cooler that matches the overall theme of the build. For instance, a white PC build will require a white cooler to match the rest of the system.
- Value For Money: Lastly, one must carefully analyze the value-for-money a cooler offers. This can be done by simply evaluating the price-and-performance ratio while also weighing in other aspects, including features, aesthetics, and sound, in contrast to its price. I made sure to cover every inch of detail, making it easier for readers to gauge the actual value a cooler offers.
Frequently Asked Questions
Yes, a 420mm AIO mostly performs better than a 360mm one.
Yes, 420mm is certainly overkill for anyone who does not require the best cooling possible.
The AIO size can be a determining factor of the cooler performance your cooler provides.
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[CPU Coolers & RAM Expert]
Hayyan Serwer is a tech enthusiast, with a love for PC building and article writing. Hayyan specializes in writing about CPU coolers and RAM kits. Hayyan has been familiar with the tech industry for over half a decade now, and has now stepped into providing quality reviews for the latest and greatest tech.
