It’s no secret that CPUs are getting hotter and hotter. Even if AMD claims that 90 degrees Celsius is “normal” for their Zen 3 chips, keeping temperatures as low as possible is always good for the longevity of your CPU. That’s where the best 280 mm AIOs come into play.
This is where AIOs really start to come into their own and begin outclassing the best air coolers. But picking the right 280 mm AIO isn’t always straightforward since they’re often more similar than different. Despite that, some products differentiate themselves based on value, aesthetics, performance, or any combination of those.
Read on to find out the ones that stood out the most for us.
Our Favorite 280 mm AIO CPU Coolers
Arctic’s Liquid Freezer II 280 made waves when it launched in 2020 and continues to be one of the best 280 mm AIO coolers you can buy right now. The Liquid Freezer II 280 combines an affordable price (good enough to also be our “best value” pick) with top-tier performance.
Gamers Nexus tested the Arctic with a Ryzen 9 3950X and a Ryzen 7 3800X, with all CPU coolers noise-normalized to 35 dBA. The Arctic handled both brilliantly, although the overclocked 3950X results are arguably a bit more impressive. Here, the Liquid Freezer II 280 managed a 52.4 degrees Celsius delta over ambient.
The Arctic Liquid Freezer II 280 manages to do this without resorting to brute force airflow and noisy fans, too. This makes its cooling prowess arguably even more impressive. Tom’s Hardware also tested the Arctic, and they recorded an impressively quiet 21.9 dBA at 50% fan speed. Even at maximum fan speed, the Arctic only registered 25.7 dBA of noise.
That’s about the same (or quieter) than the average library, according to the Federal Aviation Administration’s dBA chart. Noise won’t be an issue with the Arctic. The fact that the included Arctic P14 140 mm fans only spin up to a maximum of 1700 RPM possibly plays a part in keeping noise levels down.
The Liquid Freezer II 280 also sports a tiny fan that cools your motherboard’s voltage regulator modules (VRMs). The fan definitely works, although the roughly 5 degrees Celsius improvement in VRM temperatures with the fan is generally insignificant in the real world. After all, any case that’ll accommodate a 280 mm AIO should have enough room to keep VRMs running within spec.
The only drawback, if it is one, is the Liquid Freezer II 280’s total lack of RGB. I personally don’t have any issues with this, as I’m not a huge RGB fan. However, the Arctic may be a bit too boring if you want a bright, attention-seeking build. You can always swap the fans for some RGB fans if you need a bit of extra bling.
Yes, you can get AIOs with prettier, RGB-lit pump blocks. Our next pick, for instance, is precisely that. However, the Arctic is arguably the first (and best) choice if you want excellent liquid cooling performance for around $120 and aren’t too fussed about RGB.
EVGA’s CLC 280 is another AIO worth considering if you want a similarly no-frills, low-key 280 mm AIO. One point in favor of the EVGA product is that it’s often selling for under $90. If budget is a factor, keep your eyes open for a deal on the EVGA.
Corsair’s H115i RGB Pro XT is a refresh of the H115i Pro with new high-speed fans and a new pump block. These improvements make the Pro XT a solid, high-performance alternative to the Arctic Liquid Freezer II 280 for those of you who want a bit more bling on their AIO pump blocks.
Tests show that the H115i RGB Pro XT goes toe to toe with the Arctic when cooling a stock Intel Core i9-9900K. Yes, the Arctic is technically better by a single degree Celsius, but that’s a mostly inconsequential gap in the real world.
The margin does widen slightly when the i9-9900K’s overclocked to 5.0 GHz on all cores, but two degrees (79 for the Arctic vs. 81 for the Corsair) is hardly a problem. So, overall, the Corsair performs well and is among the best 280 mm AIOs for cooling performance.
Despite sporting relatively fast 2000 RPM Corsair ML fans, the H115i still keeps noise levels in check, even under load. Guru3d’s testing puts the H115i on par with the Arctic at 37 dBA.
That’s quite impressive and points to the possibility that there’s some room to further reduce temperatures by increasing fan speeds (and, unfortunately, noise). Corsair includes an “Extreme” profile in its iCUE software, presumably for that very reason.
Noise Measurements and Why They Differ
You may notice that the 37 dBA that Guru3d measured for the Arctic Liquid Freezer II 280 is louder than Tom’s Hardware’s 25.7 dBA measurement. That’s because different websites have different testing methodologies, equipment, and ambient noise levels.
Variables include the distance reviewers measure from or the sensitivity of their equipment. So numbers won’t always match up between sites. Ideally, noise comparisons should be done with data from the same reviewers or equipment.
As with all of Corsair’s RGB products, you’ll also use iCUE to control the LEDs on the H115i RGB Pro XT’s pump block. You get 16 RGB LEDs on the pump block that can be configured to display all of the usual lighting patterns, including “Spiral Rainbow” and “Marquee.”
You will have to live with an ugly USB cable jutting out the side of the pump block if you want to use iCUE, though. While it isn’t disastrous, we would love to see a less intrusive solution that doesn’t conflict with the pump block’s clean lines.
Overall, the Corsair H115i RGB Pro XT is another solid, commendable AIO from Corsair. While it performs worse on paper than the Arctic Liquid Freezer II 280, it’s close enough that it shouldn’t matter much. It arguably makes up for it with a better-looking RGB pump block, too.
Already gone down the RGB route with your other components and don’t want your AIO’s pump block to be the odd one out? The H115i RGB Pro XT is a safe bet.
Fractal’s new series of RGB Lumen AIOs is a striking series of products that combines the company’s sleek design language with RGB lighting. Despite not being a huge RGB fanatic, even I have to admit that these AIOs look particularly stunning.
But before we dive further into the S28 RGB’s looks, let’s cover the critical performance metrics first. After all, an AIO’s looks don’t count for much if it can’t keep a CPU cool. Hexus tested the Lumen S28 RGB with an AMD Ryzen 9 5950X and found that the Fractal turned in impressive numbers at stock clocks.
A 38.1 degrees Celsius delta on such a powerful CPU is impressive. For comparison, that’s only a single degree hotter than the much larger Arctic Liquid Freezer II 420.
The Lumen S28 RGB’s performance does come at a cost, however. It is noticeably noisier than the other AIOs in Hexus’ testing. A 33.8 dBA reading at stock clocks isn’t all that impressive, especially not when the Arctic Liquid Freezer II 420 measured 32.4 dBA in the same testing.
The Fractal’s sub-par noise levels may have something to do with the design of the AIO. Most AIOs have the pump located in the CPU block itself, a patent held by Asetek (the actual manufacturers of most AIOs on the market). Fractal’s S28 RGB was manufactured by Apaltek, who decided to build the water pump into the radiator itself.
This means that the pump is closer to the ear (and, presumably, to Hexus’ testing equipment) than most other AIOs, leading to increased noise levels. It’s not all bad, though, as this means that the S28 RGB has a much smaller pump block that honestly looks quite cute.
The small size also helps the RGB lighting diffuse evenly across the frosted top cover, adding to the S28 RGB’s aesthetic appeal. The top cover can also be detached and rotated to fit your aesthetic and orientation preferences, which is a nice little touch. The RGB doesn’t require any proprietary software and is controlled via your motherboard’s ARGB header.
All in all, the Fractal Lumen S28 RGB is one of the best-looking AIOs you can buy right now. It is a bit noisier than the competition, but if you’re after a clean, well-lit RGB AIO, then the noise might just be worth it.
RGB is all well and good, but what if you want more bling than what a bunch of LEDs can offer? If that’s the case, NZXT’s Kraken Z63 is the 280 mm AIO for you. It offers above-average liquid cooling performance while sporting a full-color, fully customizable LCD screen on the pump block.
We’ll get to the screen and aesthetics later; let’s look at how the Z63 performs first. With a simulated 250 W load (roughly equivalent to a 10th generation Intel i7 CPU), the Z63 turns in an impressive performance at only 21.2 degrees Celsius above ambient. This is at low fan speeds, too, which are more reasonable than the max fan speed tests you usually see.
The Z63 is on par with 360 mm AIOs like the Cougar Helor 360 and SilverStone Permafrost PF 360, so it’s in good company. It doesn’t resort to noisy fans to achieve these temperatures, either; AnandTech measured 35.1 dBA, which should be acceptable for most users.
So it’s a solid AIO even without the added flavor of the LCD screen. But it’s that 2.63-inch, 320 x 320 LCD screen that really sets the Kraken Z63 apart from other 280 mm AIO liquid coolers. Through NZXT’s CAM software, the LCD can display everything from useful temperature information to more aesthetic choices such as a static image or an animated. GIF of the year’s hottest meme.
Is the screen practical? Potentially, if you keep your case within easy view of your monitor. But if you ask us, the screen is all for show. There’s nothing wrong with that, of course. Just be prepared to pay a pretty penny for the privilege.
At around $250, the Z63 is a pricey AIO that won’t be in everyone’s budget. But the customizable full-color LED screen is undoubtedly a unique proposition. It wouldn’t be our first choice, but there’s no denying the novel possibilities that an LCD screen offers. Whether the novelty is worth the money will be entirely up to you and your desires.
The much cheaper NZXT X63 is a strong alternative if you want the same impressive performance and don’t need the LCD screen. You’ll save around $100 by opting for NZXT’s more conventional screenless pump block. Which, it’s worth noting, still looks great and surprisingly classy.
If you’re considering building an entire custom liquid cooling loop but want to test the waters first, Alphacool’s Eisbaer Extreme Liquid 280 is the AIO for you. Unlike all the other 280 mm AIOs on our list, the Extreme Liquid 280 is designed to be integrated into larger water cooling loops courtesy of the quick-disconnect fittings on its tubes.
These fittings mean that the pump block and radiator aren’t permanently connected to each other. So they can easily be connected to other water cooling equipment such as a GPU water block or liquid reservoir. This makes it something of a future-proof AIO, as you won’t have to get rid of it when you decide to commit to a custom loop.
But the expansion possibilities aren’t the only noteworthy aspect of the Eisbaer. It’s also a high-end AIO that can keep an overclocked Intel i7-8700K running at 66 degrees Celsius (with a 22 degrees Celsius ambient temperature). Granted, the 8700K isn’t the most recent CPU out there, but it still puts out a lot of heat once you start cranking it up to 4.8 GHz, as Guru3d did.
What’s impressive about these CPU temperature numbers is that the Alphacool AIO only measured 38 dBA on Guru3d’s decibel meter. For context, that’s the same noise level they recorded for Noctua’s
The Alphacool isn’t just as quiet as a tower cooler; it’s as quiet as a Noctua cooler. Impressive, considering the Noctua could only manage 74 degrees Celsius in the same overclocked 8700K test. This definitely puts a wrench in the traditional liquid vs. air cooler debate as far as noise is concerned.
So the Alphacool Eisbaer Extreme Liquid 280 is an excellent 280 mm AIO that can serve as the starting point for a full-on custom loop. In that sense, it’s generally without equal in the AIO world. Liquid loss due to permeation also won’t be a huge issue, as the quick-disconnect fittings make for easy refills.
But, as you might expect, that combination of qualities doesn’t come cheap, and you should expect to pay close to $300 for an Extreme Liquid 280. Painfully expensive? Yes. But it’s arguably better value than buying a cheaper AIO and then getting rid of it to buy a new CPU water block for a custom loop.
It’s a niche use case, for sure. But if the combination of high performance and expandability strikes a chord with you, this is one of your only options. That is, aside from Alphacool’s non-Extreme 280 mm Eisbaer, of course.
Radiator Sizes and You
Usually, we’d have a buying guide section here to discuss key factors you should be aware of. But buying a 280 mm AIO (or any AIO) is relatively straightforward. Just check that the AIO cooler you’re interested in will fit in your case and has mounting hardware for the CPU socket you’re using. If the answer to both is “yes,” you should be good to go.
So, instead, let’s look at a couple of rival AIO cooler sizes and see how they stack up to 280 mm AIOs.
360 mm (and Larger) AIOs
Performance-wise, 360 mm and larger AIO liquid coolers will be overkill for most users. Take a look at any of the temperature charts in this article; you’ll likely notice that the 280 mm AIOs equal or beat the 360 mm AIOs even with overclocked CPUs. Here’s the AnandTech chart for the NZXT Kraken Z63 again as an example:
The Cougar and SilverStone AIOs are 360 mm, and they perform identically to the 280 mm NZXT. They are a bit better at maximum fan speeds (~16.6 degrees Celsius for the 360s vs. 17.4 for the NZXT), but that’s still not a significant enough margin to justify the extra real estate.
A single mainstream CPU generally doesn’t produce enough heat to make a 360 mm AIO cooler worth it. However, the increased surface area and extra fan on a 360 mm AIO cooler have a less obvious advantage. It should allow you to reduce fan speeds without giving up too much performance.
Take a look at Hardware Canucks’ noise-normalized test of four different AIO cooler sizes. Note the lower temperatures on the 360 mm AIO when the total system noise was set to 38 dB overall. This indicates that the 360 mm AIO is marginally better at cooling once fan speeds are reduced.
So, if you’re aiming for the most efficient AIO cooling possible at minimal noise levels, a 360 mm or larger AIO might be worth considering. Otherwise, you’re probably better off with a 280 mm or even 240 mm AIO cooler.
240 mm AIOs
Things get slightly more complex here. 240 mm AIOs can perform just as well as 280 mm AIOs, but that relies on factors such as the AIO’s quality and fan speeds. To illustrate this, let’s look at another set of numbers from AnandTech. First, pay attention to the two results outlined in red:
These show that the Arctic Liquid Freezer II 240 performs identically to the 280 mm NZXT Z63. There’s a reason for this, which we’ll discuss shortly. But before we head there, take a look at the Deepcool and Fractal Design AIO CPU coolers outlined in green. These are also 240 mm, but perform significantly worse than the 280 mm Z63.
You might think that makes them irrelevant, but temperatures are only half of the story. Let’s look at noise levels next:
Here, you can see that the Arctic achieves its 280 mm-equalling performance by running faster fans (which produce more noise). In comparison, the Deepcool and Fractal Design 240 mm AIOs that performed worse than the Z63 all recorded significantly lower noise levels.
So, overall, there isn’t a clear-cut winner here between 240 mm and 280 mm AIO CPU coolers. If you’re looking to maximize cooling performance while minimizing noise, 280 mm AIOs are the way to go. But if you don’t need as much cooling performance or don’t mind extra noise, then 240 mm AIOs are perfectly viable.
Choosing the best 280 mm AIO cooler is more a matter of fine details than any drastic differences in cooling performance between products. Sure, there’s a degree or two here and there, but by and large, all of our picks will be more than capable of cooling even the hottest mainstream CPU with room to spare.
Instead, choosing the right 280 mm liquid cooler for you will depend on many surrounding factors. There’s price-to-performance, noise levels, aesthetics, and availability (amongst others) to consider. On balance, we think the Arctic Liquid Freezer II 280 is the best choice for most users. Still, we wouldn’t begrudge anyone for picking any of the other four AIOs we’ve listed here.
As always, happy hunting!