AiO CPU cooling – is it worth it? Which one to buy?


The popularity of All in One water coolers is growing pretty rapidly. With such a wide variety of models available on the market that, at first glance, don’t seem to vary much form each other, it’s hard to choose the one that will best suit our needs. Let us help you out by addressing a few crucial issues that you should be aware of.

It’s not all about water, y’know

Water itself doesn’t do all the magic. It just conducts thermal energy from the block to the radiator where heat is ultimately dissipated to the air. That is why the radiator surface is extremely important and why AiOs with 1x 120 mm or 1x 140 mm radiators have worse performance than good air coolers. Additionally these AiOs are usually loud and expensive. For this reason I find it really hard to recommend them to anyone other than users who can’t fit a high performance air cooler in their PC case. 2x 120, 3x 120 and 2x 140mm variants have a way bigger heat dissipation surface and usually exceed the performance of the top air coolers.

kelvin s36It might seem that a sealed AiO is the best way to go, but in fact, water from a great many water cooling loops very slowly evaporates over time. That is why, after long term usage, non-expandable AiOs can accumulate air bubbles (creating air lock) that lower the performance of the radiator, and make the pump work very loudly or even cause it to fail.

With this in mind, I strongly recommend sets that can be disassembled. Fluid that is inside them can be refilled or even replaced. And replacement is quite useful for other reasons: corrosion inhibitors and the anti-alge properties of all fluids degrade over time and sets that can be disassembled can also be upgraded with, for example, a second water block and/or radiator. Or a user can simply exchange tubing for something longer or of a different colour, like in this bulid. These are all advantages that cannot be overlooked.

It’s also worth noting that pumps from AiO liquid cooling sets are usually rather loud so if you are planning to build a really quiet PC you are limited to a high end air cooler with a high quality fan or a custom water loop. If you buy the pump separately you can choose a model that operates more quietly than the pumps usually used in AiOs.

H240X2PRESTIGEIMG2It is important to remember that a pump is a mechanical element that can fail. And the set itself can leak and possibly kill your PC parts. These are, of course, rather unlikely events but they can happen. Air cooling is just a bit safer side than liquid cooling. There is less chance of failure and even if it occurs there is a smaller chance that it will cause serious damage.

It is usually better if the pump is not integrated with a water block.

It’s also worth bearing in mind that copper radiators perform significantly better than aluminium ones.

If you are going to go for an AiO, it’s best to be sure that you understand the limitations of your options and choose wisely. Good quality air coolers might very well be the better choice in ways that are important to your specific needs. If an AiO is poor, the air cooler can outperform it in literally all aspects. Don’t get me wrong, though. I write this not to discourage you from buying such a set. A lot of people consider AiOs to be the perfect solution and they may be right. However,  when you are making that choice, it is essential to be aware of exactly what it does, exactly what you need, and exactly which one will do the job best.

So, which ones are the best?

Taking into account the criteria outlined above, we are actually left with not too many models to choose from, since vast majority of sets cannot be disassembled. But these are worth checking out:

  • Alphacool / Cooler Master Eisberg 240
  • EKWB EK-XLC Predator 240 / 360
  • Fractal Design Kelvin S24 / S36
  • Swiftech H220 / H240 / H320

qdc 360

All of them have a radiator bigger than 1x 120 / 140 mm and are expandable. Personally, I find the Predator with QDC fittings really appealing. This set has great fans and a good pump included plus it is super convenient to expand with an additional pre-filled VGA full-cover water block, for example.

Keep in mind, however, that we are getting really close to custom water cooling loops now, where you can choose every single part that suits you best. On the other hand, this would require much more knowledge in order to make the right choices and greater awareness of the assembly process. I personally have custom liquid cooling but I understand that it is not for everybody. You really have to want it and be willing to spend quite a lot of money to complete it.


As I have said, low end AiO sets with small aluminium radiators that are not expandable are something that I would definitely discourage you from buying. Despite being low end, they are still rather pricey and, in my view, just not worth it. From all the other options though, it is fair to say that there is not one perfect solution. Air cooling, AiO, and custom water cooling have their pros and cons.  Have a good look at what’s out there. Air cooling is still standing strong! And if you really want AiO – go for something decent.


Grzegorz Iwan
Amateur extreme overclocker from Poland, one of two Poles who broke the 8 GHz CPU clock barrier. Hardware enthusiast and collector, envoy of PCMasterRace philosophy; You can find ivanov's fanpage here here.