GuidesComparisons240mm vs 280mm AIO Coolers- Which One Should You Get?

240mm vs 280mm AIO Coolers- Which One Should You Get?

Which one is a better fit for your rig? Watch as we compare both AIOs and help you make an educated decision about your purchase.

Expert Verified By

280mm AIO

Rated: 8/10

240mm AIO

Rated: 9/10

Pros And Cons

240mm AIO✅ Cheaper
✅ Relatively Quieter
❌ Smaller Radiator
280mm AIO✅ Higher Static Pressure
✅ Better cooling.
❌ Expensive
Key Takeaways
  • Both AIOs come with two fans in the radiator.
  • 240mm consists of two 120mm fans whereas the 280 mm consists of two 140 mm fans.
  • The 280mm is slightly better in terms of cooling whereas the 240mm runs quieter. 
  • Price-to-performance ratio heavily benefits the 240mm so that’s what we recommend.

Comparison Table

ModelDeepcool Castle 280EXDeepcool Castle 240EX
Cooler Size280mm240mm
Net Weight1600 g1421 g
Radiator Dimensions322×138×27 mm282×120×27 mm
Tube length380 mm380 mm
Pump Dimensions86 ×75×71 mm86×75×71 mm
Pump Speed2550 RPM±10%2550 RPM±10%
Pump Noise17.8 dB(A)17.8 dB(A)
Pump Connector3-pin3-pin
Pump Rated Voltage12 VDC12 VDC
Pump Rated Current0.2 A0.2 A
Pump Power Consumption2.4 W2.4 W
Fan Dimensions140×140×25 mm120×120×25 mm
Fan Speed400~1600 RPM±10%500~1800 RPM±10%
Fan Airflow97.03 CFM69.34 CFM
Fan Air Pressure2.00 mmAq2.33 mmAq
Fan Noise≤39.8 dB(A)≤32 dB(A)
Fan Rated Voltage12 VDC12 VDC
Fan Rated Current0.3 A0.15 A
Fan Power Consumption3.6 W1.8 W
LED TypeAddressable RGB LEDAddressable RGB LED
LED Connector3-pin(+5V-D-G)3-pin(+5V-D-G)
LED Rated Voltage5 VDC5 VDC
LED Power Consumption2.25 W(PUMP)2.25 W(PUMP)

Architectural Differences

  1. Cooling Efficiency: Since a 280mm AIO boasts a bigger radiator and fan size than a 240mm AIO, it will boast better cooling efficiency as well.
  2. Fan Size: 280mm AIOs typically have two 140mm fans, while 240mm AIOs are featured with two smaller 120mm fans. Since the 280mm AIOs can often accommodate larger 140mm fans, they potentially offer better airflow. 
  3. Fan Configuration: Both 240mm and 280mm AIOs come with the same exact fan configuration. The configuration includes a dual fan setup in the radiator. Both AIOs only differ in fan size.
  4. Radiator Thickness and FPI: When talking about radiators, 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.
  5. Radiator Dimensions: Exact radiator dimensions would depend on the brand and model of the AIO you buy. However, the 280mm AIOs generally have larger radiator dimensions compared to 240mm AIOs. Since they need to accommodate bigger fans.
  6. Noise Levels: Bigger fans and radiators mean a higher noise level, therefore we can expect the 280mm AIO to be noisier than the small 240mm AIO.

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. 

280mm vs 240mm AIO – Benchmarks

Test Bench

Testing 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

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


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.


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. 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 the 120w tests 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

Verdict: 240mm vs 280mm AIOs

240mm AIO: In our assessment, the performance difference between both fans was negligible. The 240mm AIOs are the sweet spot for mid-to-high range builds and will give you an overclocking room as well. Not to mention, they run quietly and cost less as well.

280mm AIO: On the other hand, the 280mm AIO provides slightly better cooling temperature levels but louder noise levels than the 220mm AIO, which can be of nuisance. It is also more expensive compared to the 240mm AIO.

We compared 240mm vs 280mm AIOs of the same series, with all possible variables removed. It concludes that 240mm and 280mm AIO differ too little in performanceBased on this, 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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