We recently published a benchmarking test of a large number of air coolers for modern processors. This time it is the turn of water coolers! For this article we tested 32 ready-to-use (all-in-one) water coolers, i.e. models that are completely assembled and filled from the box. The prices of the tested kits range from around 65 dollars to more than three times the price. That raises the question: which water cooler to buy to cool your PC? After reading this article you will have the answer.
A water cooling system consists, in large strokes, of three components: a metal water block that is placed on the processor through which (cooled) water flows, a radiator in which the heated water cools down again and a pump that ensures that the water circulates between radiator and water block. For all-in-one water coolers such as those tested here, the pump is usually integrated in the water block mounted on the processor.
The idea behind water cooling is that the heat generated by the processor is not transferred directly from the processor to the ambient air, but is transported to another location by means of a liquid and then transferred to the ambient air.
Benefits of water cooling
Water cooling, therefore, has a number of potential advantages over air cooling. The most important of these is that where air coolers circulate the heated air inside, the radiator of a water cooler is usually mounted on the front, rear or top of the chassis, where the heated air is blown directly out of the chassis ensuring a lower temperature inside the chassis. As a result, fewer case fans are needed to bring cool air into the case, and warm air to blow out. Although water coolers are not per se quieter than air coolers, the combination of water cooling and less (fast running) case fans is often quieter than when you use purely air cooling.
Another advantage of water cooling is that it is possible to lower the temperature of the ambient air further than with air cooling. Certainly, systems with large radiators that provide space for two or even three fans usually offer much more heat exchange capacity than an average air cooler. Of course, there are exceptions to this rule - extremely large air coolers such as the Noctua NH-D15 beat some water coolers, but most of the water coolers tested by us perform better than almost all the air coolers we have tested.
Another type of air cooling
In this article we are talking about water cooling and air cooling, but in both cases the heat generated by the processor is transferred to a metal heat sink, through which cold air is blown, which absorbs the heat from the heat sink. The difference between water and air coolers is that the metallic heat sink of air coolers connects directly (or via metal heat pipes) to the processor, while in the case of water coolers a liquid is used to transport the heat from the processor to a heat sink at a different location. Both have their own advantages and disadvantages, but for both, it is never possible to reduce the temperature of the processor below the temperature of the ambient air used for cooling.