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240mm vs 280mm AIO

The race for better cooling and overclocking abilities is leading us into an era where All in One Coolers are becoming more and more common. In the modern era, overclocking is becoming more and more common, as well as easier. Most motherboard manufacturers provide features that allow you to automatically overclock your CPU according to your cooling solution. Air Coolers are still the most common form of cooling. However, if you’re an enthusiast or even a beginner in overclocking, you’ll want to invest in at least a decent All in One Cooler with newer AMD or Intel CPUs. AIO coolers remove the installation hassle of liquid CPUs, but the leakage risks remain. The majority of 240mm AIO coolers will outperform any air cooler on the market.

AIO Coolers, therefore, provide a much-needed middle ground between air coolers and liquid/water coolers, both in terms of price and performance. There are five types of AIO coolers based on the size of the radiator: 120mm, 240mm, 280mm, 360mm, and 420mm. 420mm AIOs feature three 140mm fans and are still rare, as they won’t fit in a majority of the cases.

The argument of 240mm vs 280mm AIO is a common dilemma between overclockers. Therefore, today, we will be differentiating between 240mm AIO vs 280mm AIO, so we can eliminate that dilemma. Our article will compare Benchmarks, Temperatures, Noise, Overclocking, and better choices given the circumstances. 

What is AIO Cooling And How Does It Work?

AIO cooling or closed-loop liquid cooling, refers to the use of All in One Coolers (AIOs). These all-in-one coolers combine the principles of air coolers and open-loop liquid coolers. Hence, they use air and water/liquid as the cooling medium.

AIO coolers consist of two important components. The first component is the radiator, and second is the fan.

Liquid Cooling Process (Image Courtesy: Intel)

In this process, heat from the CPU’s IHS (Internal Heat Spreader) is effectively transferred to the CPU block through the thermal compound. The heat then moves through the block and into the liquid in the pump. The liquid moves toward the radiator. The radiator is a heat exchange unit and its purpose is to transfer heat away from the CPU. So, as the liquid moves through the horizontal channels of the radiator, the aluminum fins direct heat away from the channels. The heat is then directed away from the fins and away from the radiator through the fan(s). This heat then moves out of the case through your case fans.

Basic and Key Differences: 240mm vs 280mm AIO

To start, a 240mm AIO consists of a 240mm radiator. Same way, a 280mm AIO consists of a 280mm radiator. Let’s look at a breakdown of some of the key differences between 240mm and 280mm AIOs before we get into details,

Size of AIO 240 millimeters 280 millimeters
Radiator Size 240mm 280 mm
Fan Size 2x 120mm Fans 2x 140mm Fans
Radiator Dimensions Larger radiator; exact dimensions vary Smaller radiator; exact dimensions vary
Fan Dimensions 120mm; exact dimensions vary 140mm; exact dimension vary

240mm vs 280mm AIOs

In short, the main differences that change between the two types of AIOs are in the fans and the radiator. The variance in radiator sizes means a change of surface area. So a bigger radiator offers more surface area to dissipate heat. The difference in fan sizes, also leads to a difference in the volume of air the fan can dissipate. It also affects maximum fan speeds on a small scale. This in turn, results in differences in airflow and fan noise. Typically, you can expect the larger 140mm fan to run faster AND dissipate more heat. But at the same time, you’ll be dealing with somewhat higher noise levels at high RPMs. The difference in noise and maximum fan speeds varies from model to model, but only on a small scale.

Do note that there’s also a difference in the sizes of the tubes in the 240mm vs 280mm argument. 240mm AIOs have 350mm long tubing, while the tube length of 280mm AIOs is 400mm. This leads us to the argument of case compatibility, which will be discussed later.

Different Changes in Different Brands or Models

If we compare 240mm vs 280mm AIOs of different brands or series, then there’s lots of factors that change. This will include the pump design, the fans, the radiator design, as well as RGB and non-RGB features. Another difference is the tubing design, the two common ones being FEP rubber and EDPM. FEP (Fluorinated Ethylene Propene) rubber is rigid and difficult to install. EDPM rubber is much more flexible, but also more expensive. For an apples-to-apples comparison, we will be comparing AIOs of the same series.

240mm vs 280mm AIO: Performance

Before we look at the performance difference, we will be looking at a few key factors upon which performance depends.

Fan Size

As we mentioned above, the difference in the sizes of the radiator and fans translate into a difference in performance. This means that the 280mm AIOs will give a slightly better performance than the 240mm AIOs at the same RPM. However, this also means that the 280mm AIOs will produce slightly more noise. However, the 280mm fans will give you an equivalent performance to 240mm at lower RPMs. Hence, the noise to performance argument is a mixed bag when it comes to the fan sizes.

Fan Static Pressure

The fan’s static pressure is basically a measure of the resistant pressure a fan has to oppose to move air in the desired direction. Generally, all CPU cooling fans are designed for high static pressure, rather than high airflow. Larger fans have more static pressure, which gives better cooling as a result. The static pressure of the fan also varies slightly from different models of fans. Different AIOs have different fans, and hence different static pressure ratings (CFM). Higher the CFM rating, the more effective it is. This is the reason it’s better to compare AIO coolers from the same series, with the same fans.

Radiator Size

The second biggest factor after the fan size is the size of the radiator. In fact, it’s essentially just as important as fan size. The fans are attached to the radiator and the heat is actually dissipated through the fins of the radiator. Larger the radiator, the higher the number of fins and vice versa. So, the 280mm radiator will have more fins when comparing models of the same series. This, in turn, means more area for heat dissipation. Consequently, larger radiator equals better performance.

Radiator Thickness and FPI

When talking radiators, it’s very important to note that an AIO cooler (having a thicker radiator) is more efficient than a thinner one. Consequently, a 240mm AIO cooler might actually outperform a 280mm AIO cooler, if its radiator is thicker in size.

Furthermore, another important factor to note is the “Fins Per Inch” or FPI of the radiator. The fins are the zig-zag-shaped (usually aluminum) materials that form the base of the AIO radiator. FPI refers to the density of these fins. So, higher FPI means more density, and more density means more heat dissipation.

Performance Difference

Now, we’ll be looking at the performance difference in regards to 240mm vs 280mm AIOs. We’ll be using Phanteks’ Glacier One 240mm and 280mm AIOs. Since both the AIOs belong to the same series, having the same radiator and fan designs. The only difference is of course, in the radiator and fan sizes. This way, all other variables are removed as both the AIOs feature Asetek’s Gen 7 Pump Design. They also use the same 27mm thick aluminum radiators. The 240mm variant is priced at $124.99, while the 280mm variant has an MSRP of $139.99.

Note that the two fans differ in maximum speeds, and therefore, noise levels.

Fan Size 120mm 140mm
Fan Speeds 500 RPM – 2200 RPM 500 RPM – 2000 RPM
Noise Levels 18 db(A) – 34.2 db(A) 18 db(A) – 39.1 db(A)

120mm vs 140mm Fan Differences

So the larger fan will make more noise compared to the 120mm, at the same fan speeds.

Test Bench

  • CPU: Core i9-10980XE
  • Motherboard: Asus X299 Edition
  • Memory: G. Skill Trident Z 3200 MHz
  • Graphics Card: Asus Strix RTX 2080 Ti OC
  • Storage: Samsung 850 EVO 1 TB NVMe SSD
  • Power Supply: be Quiet! Dark Power Pro 11 750w
  • Casing: Meshify S2

Testing Conditions

For the best possible accuracy, we will be testing the two coolers under certain conditions. We will carry out our tests at constant fan speeds at different wattage loads of 120w, 165w, and 260w. Our motherboard allows us to set wattage levels on the CPU and the total CPU wattage does not extend beyond that. These different loads represent stock, overclocked, and very high wattage CPUs.

The pump speed will be kept at a constant 50%. The ambient noise is 34.2 dBA.

The CPU fan speed is adjusted according to the CPU temperatures, in the following order:

  • 40°C to 60°C = 20% to 55% Fan Speed
  • 60°C to 80°C = 55% to 100% Fan Speed
  • Greater than 80°C = 100% Fan Speed

We will also be testing Asetek’s 120mm AIO cooler to see how much better 240mm and 280mm coolers are. Phanteks does not provide a 120mm variant. However, the 120mm we’re using has the same fans as the Glacier One series.

Our stress test is AIDA64, and the results are derived after 30 straight minutes of stress testing.

120W Noise Normalized Temperatures

Room Temperature 27C: Noise Without Cooler = 34.2 DB(A) – Full Core Load – 38 dB(A) Constant

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165W Noise Normalized Temperatures

Room TEmperature: 22C – Noise Without Cooler 34.2 dB(A) – Full Core Load – 38 db(A) Constant.

[wpcharts type=”horizontalbarchart” bgcolor=”gray:gray:yellow,blue:gray:yellow,random:gray:yellow,orange:gray:yellow” min=”0″ max=”100″ legend=”false” titles=”Glacier One 240mm, Glacier One 280mm, Astek Gen 7 120mm” values=”58, 56, 61″]

260W Noise Normalized Temperatures

Room Temperature: 22C – Noise Without Cooler = 34.2 dB(A) – Full Core Load – 38 dB(A) Constant

[wpcharts type=”horizontalbarchart” bgcolor=”gray:gray:yellow,blue:gray:yellow,random:gray:yellow,orange:gray:yellow” min=”0″ max=”100″ legend=”false” titles=”Glacier One 240mm, Glacier One 280mm, Astek Gen 7 120mm” values=”84, 81, 97″]

We’ll only be discussing the 165w and 260w load tests, since the 120w load test yields remarkably similar results between the three coolers.


Now you’ll understand that carrying out the tests at different loads makes sense. Basically, this gives us a representation of three different types of CPUs. The 120w Load represents the mid-range i5 CPUs and the Ryzen 5 chips. The 165w Load translates into the higher-end Core i7 and Ryzen 7 Chips. 165w is also the base TDP for the 10980XE. On the other hand, the 260w Load stands for the overclocked Ryzen 9 and i9 CPUs.

We see that at 120w Load, all three coolers remain at identical temperatures after 30 minutes of Load. But once we crank the loads to 165 and 260w, the temperature difference becomes more significant. When the Load is increased to 260w, the temperatures jump to 97°C for the 120mm AIO, so it’s obviously too hot to handle for the 120mm AIO. There are only a few degrees of temperature difference between the 240mm and 280mm coolers at 165w and 260w loads. The 280mm variant remains 2 degrees cooler at 165w and 3 degrees cooler at 260w. Increased fan speeds beyond a particular limit seem to give us diminishing returns, as there’s not much reduction in temperatures.


For reference, 38 dBA of noise a few inches away from your running PC is barely noticeable.

In our noise normalized tests, we see that at 50% pump speed and fan speed at constant, the 240mm and 280mm differ. In the 165w load test, the 280mm variant cools better at the same noise levels as the 240mm variant. This was certainly expected. We explained above how larger fans deliver better cooling at the same speed than a smaller fan. At 52°C, the 280mm is louder because the 140mm fans are louder at the same RPM as the 120mm fans. When talking about the 260w load test, the 280mm variant, again, coolers better at the same noise levels. The 280mm then delivers more noise as it beats the 240mm by 3 degrees.

Temperature-to-Noise Ratio at 165W Load

Again, we will be discussing only 165w and 260w load tests, since 120w test gave similar results. So at 165 watts of Load, the 280mm variant cools better at the same noise levels. You can see the orange line representing the 280mm extends to 50 decibels. This is because the 140mm fans are louder at max RPM than 120mm ones.

240mm vs 280mm temperatures
Temperature-to-Noise Comparison at 165W

Temperature-to-Noise Ratio at 260W Load

We see the same results at 260 watts of Load. The 280mm variant coolers more effectively at the same decibels. The 280mm variant runs louder while keeping our CPU 2 degrees Celsius cooler, compared to the 240mm model.

Temperature-to-Nosie Comparison at 260W
Temperature-to-Nosie Comparison at 260W

What To Make Of The Performance Tests?

Summarizing our performance tests in short, we learn that the 240mm vs 280mm competition is almost even. The 280mm variant runs our CPU slightly cooler at high loads, but it also produces more noise at maximum fan speeds.

Overclocking 240mm & 280mm AIO

Most aftermarket air coolers can cool at least the mid-range CPUs adequately at stock settings. When overclocking is necessary, that’s exactly where AIO coolers come into the frame. Referring to our table below, if your AIO size matches the particular CPU wattage, you can expect to have decent room for overclocking. Our CPU temperatures benchmarks with the Phanteks Glacier One series showed that both the 240mm and 280mm variants kept the 10980XE under 60 degrees Celsius on a 160w load. You can, therefore, use a Ryzen 7 3800x or an i7-11700K with either the 240mm or 280mm coolers, and you’ll be able to overclock them, most likely.

Case Compatibility

A significant factor that distinguishes air coolers from AIO and liquid coolers, is case compatibility. For air coolers, the job is simple. The only thing you need to worry about is the width of the case. Moreover, pretty much every case manufacturer specifically mentions width available to accommodate air coolers.

Image Courtesy: Tom’s Hardware

For AIO and liquid coolers, however, the case is different. And the actual problem is that there are no sets of standards for clearance of AIO and liquid coolers. The hurdle is that the size of the radiators is always somewhat larger than the total size of the fan(s) on the radiator. So the radiator of a 240mm AIO cooler (having two 120mm fans) will be slightly larger than the two fans on it. So, clearance for 2x 120mm fans in a particular area (such as the front of the case) does not actually mean you can fit a 240mm AIO radiator there.

The casing compatibility factor in the 240mm vs 280mm argument also comes into play when we talk about different sized casings. This difference isn’t very significant in comparing 240mm vs 280mm AIOs since they both have long enough tubing to be accommodated in most mid-sized ATX cases. The longer tubing would prove a hurdle in some smaller mini-ITX cases in which there isn’t enough width or length to accommodate the long tubes. The problem would also likely arise with a 120mm AIO, which only has 300mm long tubing. This tubing would likely struggle to reach the front section of many full tower cases, and even some mid-tower ones.

Compatibility for 240mm AIOs

Now, let’s talk case compatibility in regards to the topic at hand, 240mm vs 280mm AIO coolers. Generally, most cases have mounting space for 120 mm (case) fans. Thus, as a general rule of thumb, we can say that most mid-tower ATX cases will have at least one spot to fit a 240mm AIO cooler. So, 240mm AIO coolers are universally more compatible than 280mm AIOs coolers. But this is not wholly applicable, of course.

Compatibility for 280mm AIOs

Things take a turn when talking about 280mm AIOs. As we mentioned, most cases have mounting space for 120mm fans. Consequently, the compatibility for a 280mm AIO depends entirely upon the casing.

Dealing With Compatibility Issues

Fortunately, most ATX cases you can find in the market from common brands (Corsair, NZXT, Cooler Master, Phanteks, and others) will support both 240mm and 280mm AIOs. Again, it depends on the particular case. The best way to deal with this is to research the particular case you’re interested in and read reviews. Normally it is best to start by looking for “240mm or 280mm cooler compatible” cases since this is the biggest problem of case compatibility.

All cases will have compatibility specifications mentioned on their respective websites. These will tell you where on the case you can attach which type of AIO.

Both AIOs in Terms of Budget

In our detailed articles about the Best 240mm AIO Coolers and Best 280mm AIO Coolers, you can get a basic idea of the price points of the respective AIO coolers. We’ve discussed coolers at different price points in these articles. Now obviously, the prices of these coolers will vary depending on features like RGB, and factors like which pump they use.

The cheaper 240mm AIOs can be found well under the range of $100. One of the most popular options in this range is Cooler Master MasterLiquid ML240L V2 RGB, which comes in at around $80. Another popular and cheap option is Arctic’s Liquid Freezer II 240mm, priced around $90. The more expensive 240mm coolers go up to the mid-to-high 100s. One of the in-demand coolers in this range is the Corsair iCue H100i Elite Capillex, which costs around $150. This Cooler has RGB fans and the block is RGB illuminated as well. Both the RGBs can be controlled through Corsair’s software.

On the other hand, 280mm AIOs hardly fall below the $100 range. Most likely, you’ll only be finding these prices in case of discounts. Still, when talking about “cheap options,” one popular choice is the Arctic Liquid Freezer II 280mm. This Cooler is priced just above 100 dollars and is one of the cheapest options, while being popular at the same time. EVGA’s CLC 280mm is another incredibly popular option which is priced at around $140. One of the pricier yet sought-after options is NZXT Kraken x63 280mm, which would set you back around $184.

Now, we’ll do a little price breakdown for the two types of AIOs, below:

Type of AIO Entry Level Mid-Range Premium
240mm $70-$95 $96-$120 $120-$170
280mm $109-$130 $130-160 $160-$200

240mm vs 280mm AIO Price Table

Which AIO size would be ideal for you?

The temperature differences at the higher wattage, basically speak for the fact that the larger radiator and/or fans will only be more helpful when there’s a larger and more powerful CPU in question. Hence, the 280mm variant will be more useful for higher-end overclocked CPUs, like the Intel i9 and Ryzen 9 Series. If your workload is not very intense, and you’re running a non overclocked i9/i7/Ryzen 7/Ryzen 9 CPU, then the performance gap between the 240mm and 280mm AIOs is so insignificant that it makes no sense to go with the 280mm variant. We will break down the recommended AIO size, for different wattages, in a nutshell:

Wattage Levels 65w or Less 65w-125w 125w-180w 180w or More
Reference Intel/AMD Model Ryzen 3 5300G / i5-11400F Ryzen 5 3600x / i5-11600K Ryzen 7 3800x / i7-11700K Ryzen 9 5950x / i9-11900K
Recommended AIO Size 120mm 240mm 280mm 360mm

240mm vs 280mm AIO Compatibility Table

Note that this table is just shown to give you a rough idea of what you might need. There are factors to keep in mind like overall airflow, as well as local climate and room temperatures. So, a 240mm AIO would be plenty for i7 or Ryzen 7 CPUs and would allow for overclocking. On the other hand, a 280mm variant would adequately cool the higher-end Ryzen 7 and i7 systems, and even Ryzen 9 and i9 CPUs. 120mm AIOs, on the other hand, will easily cool Ryzen 7 and i7 CPUs, but probably won’t allow for overclocking.

Verdict: 240mm vs 280mm AIOs

We compared 240mm vs 280mm AIOs of the same series, with all possible variables removed but the radiator and fan sizes. It concludes that 240mm and 280mm AIOs differ far too little in performance but are reasonable in price. 240mm AIOs are the sweet spot for mid-to-high range builds and will give you overclocking room as well. On the other hand, 280mm AIOs give slightly better performance, at a worse price-to-performance ratio.

Based on this, if you want to choose between a 240mm and 280mm AIO (in the case that both will fit into your case), then you should go with a 240mm. If, however, you somehow find a 280mm AIO that’s cheaper than a 240mm one, then by all means you should go with the 280mm.

Frequently Asked Questions

Can a 240mm liquid cooler fit in a 280mm liquid cooler?

No, since both the radiators use different fan sizes, they can’t fit on one another. A 240mm radiator uses 2x 120mm fans. On the other hand, a 280mm radiator consists of 2x 140mm fans.

Is a 280mm radiator better than a 240mm radiator?

If you compare 240mm and 280mm radiators of the same model (the rest of the dimensions being the same, having the same block and pump), then a 280mm radiator will indeed be better. This is simply because a 280mm radiator has a larger surface to dissipate more heat per second.

Is a 240mm radiator taller than a 280mm radiator?

The exact length between the two radiator sizes vary from model to model. Typically a 240mm radiator will be taller than a 280mm one. For example, the Phanteks’ Glacier One 240mm has a 273mm tall radiator, while the 280mm counterpart is 313mm tall.

Should I upgrade my 240mm AIO to a 280mm AIO?

We saw that at high loads, the 240mm and 280mm AIOs differed only by a few degrees in temperature. The performance difference is far too minor when we consider the price difference. You’ll be paying at least $30-$40 dollars extra for a 280mm vs a 240mm, for a minimal cooling difference. If your 240mm AIO is inadequate for your needs, consider an upgrade to a 360mm AIO for a real, noticeable difference in performance.

Which brand should I choose for my AIO cooler?

When talking about all-in-one liquid coolers, there are a few brands that you can’t go wrong with. We’ve discussed a few of the brands in the “budget” section. Typically, you can trust brands like NZXT, Corsair, Cooler Master, Phanteks or Arctic. These 5 brands are ruling the liquid cooler market at present.


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