No modern processor can be operated without an additional cooling element. As soon as the processing power is needed, the current inside causes electrical resistance, and this resistance heats the CPU. The more powerful it is, the higher the heating. If a CPU overheats, it will shut down if necessary, but it will not break Accordingly, for small, mobile processors, simple derivation using a copper element is sometimes sufficient. In a gaming PC, a workstation, or a server, however, solutions are required that can effectively dissipate heat. Only in this way can the full utilization of the computing power be achieved, because otherwise the processor is forced to throttle its performance or even provoke a shutdown.
How useful is a new CPU cooler?
Typically, a new processor is delivered with a suitable CPU cooler (“boxed CPU”), which, if you look closely at the instructions, actually has to be used to receive the guarantee. And it serves its purpose: the CPU is always kept at an acceptable temperature level. Our test also shows that even smaller tower coolers are only half as loud and easily stay 10 to 20 °C colder. This also results in smaller temperature fluctuations, which would most likely shorten the lifespan of the processor in the long term. Mind you, all processor fans in our test were able to outperform the standard cooler, usually significantly. This is exactly why it is only worth using the cooler supplied by the chip manufacturer in simple office systems that are rarely used. Anyone who sets up a new system or simply uses the simple standard model always benefits from a better CPU cooler.
Two points play a crucial role: volume and cooling performance. In a PC for the living room or office, minimal fan noise will be crucial. In a gaming PC and other powerful systems, it is the cooling performance that is of particular importance, and not just with overclocked processors.
Air cooling, water cooling, or completely passive: ambiguous
The question remains which cooler principle works best? Our test of the CPU coolers shows that water cooling and classic heatsinks with fans are on par in terms of both temperature development and operating noise. However, the price for water cooling tends to be higher because of lighting effects and of course, a water pump is installed.
In addition, material fatigue during water cooling can lead to serious damage or even destruction of the PC system. However, careful installation without overstretching the water pipes should make this extremely unlikely, if not impossible, especially with well-known manufacturers, especially since the completely closed cooling systems, whose water circuit never needs to be touched, are considered extremely reliable. However, we strongly advise against using no-name water cooling systems.
Passive solutions, on the other hand, perform remarkably poorly. In addition to the Noctua NH-P1 from our test, which is offered passively, all large heat sinks can, at least theoretically, also be used without a fan.
However, significant heating must be accepted, at least under load. At the same time, the differences in noise are so small that we always recommend a CPU cooler with active ventilation. This is not noticeable inside the PC case at low speed, but still reduces the maximum temperature by 10 °C or more.
Influence of CPU cooler color
So-called “black bodies” release their heat particularly effectively into the environment. However, this does not depend on the visible color of the heat sink and fans. Such a body is black in the infrared range, which the human eye cannot perceive. This means that it absorbs all frequencies of infrared light, which is responsible for thermal radiation.
This applies to the vast majority of metal surfaces, both treated and untreated. Finally, white-painted radiators also radiate heat very well. So whether the CPU cooler is black, white, or neon pink doesn’t matter for its cooling performance. It is most likely that an unpainted surface will perform slightly better than a painted one.
In addition to heat conduction in the heat sink and the heat transport of the heated air or water, heat radiation is only one aspect that influences the cooling performance of the processor cooler.
Installing the CPU cooler
We did not find any particular difficulties during installation. All material was sorted sensibly and mostly labeled. If particularly long or delicate tools were also required, they were included. Otherwise, an additional Phillips screwdriver was sufficient.
The base must fit
The question of LGA 1151, 115x, 1200, 1700 or AM3+, AM4, and AM5 as well as 2011-3 or sTRX4 rarely arises. The well-known manufacturers of CPU coolers supply the required material for most CPU sockets directly.
Of course, the fact that the dimensions of LGA 1155 to 1150 and 1151 to 1200 have not changed helps here. AMD also used the same socket AM4 from 2017 to 2022, before a new and technically different socket was introduced with AM5. However, this still uses the same hole spacing and base height, so everything is completely compatible. The manufacturers also list all supported sockets in the description and technical data. The LGA 115x, 1200, and AM4 sockets are supported by almost all CPU cooler models we tested.
An exception is the Arctic with the Alpine and the Freezer. Both cooler models are available in a version for AMD or Intel. With the Alpine, there are even different versions for the LGA 1200 and LGA 1700 sockets because they are clicked directly onto the mainboard and do not require any additional installation material.
It can also be noted that almost all manufacturers either already include material for Intel’s new CPU socket LGA 1700, which has grown slightly, or make it available free of charge. To use this, you usually have to submit an invoice for the CPU cooler in question and the new mainboard. This was confirmed by all the manufacturers we tested who have prepared their coolers for AMD and Intel alike.
Liked instructions
The installation instructions should be positively highlighted. They were detailed and well-explained for all CPU coolers. What is important here is to immediately orient yourself towards the side with the correct base. Apart from the Noctua NH-U12S Redux, the associated parts were also clearly labeled.
However, the Arctic takes a different approach. There are no instructions included here, but rather a QR code that directs you to the appropriate website. The basic idea makes sense because a smartphone is almost always at hand and images and small animations can be presented better online. Unfortunately, not a single QR code led to the correct page. Fortunately, she was still able to be found in the end.
Use thermal paste in doses
For optimal heat transfer between the processor and the base of the heat sink, there should be direct contact between both parts over the entire surface. Because there will always be slight unevenness, thermal paste is used to close these tiny gaps, which are only a fraction of a millimeter in size.
Too much thermal paste can weaken the performance of the cooler
The thermal paste should be used in appropriate doses. In addition to the manufacturers of CPU coolers, Intel, for example, also cites a grain of rice as a comparison size. This tiny dab should be applied exactly in the middle. By placing the heat sink, is distributed evenly and as thinly as possible between the two metal surfaces.
The reason for the economical approach is the thermal conductivity of the materials. While air performs extremely poorly here, the paste manages to transfer an average of 200 times as much heat over the same area. However, the most commonly used material, aluminum, outperforms typical thermal paste by at least a factor of 20.
Ideally, metal-to-metal contact would be best. Because this can never be done without the inclusion of air, the paste consisting of silicone and metal powder is applied as sparingly as possible. If the substance is already on the contact surface of the CPU cooler, this step is of course not necessary.
For straight positioning and therefore optimal contact and distribution of the pastes, the screws should always be tightened alternately or crosswise. After two turns at the latest, the next screw is changed. Shortly before the end, it is changed after every half-turn until the heat sink is firmly seated.
The contact pressure
While the installation is generally very simple and can be a little more complicated for large water cooling systems with additional cables and controls, there are occasional warnings that the contact pressure of the cooler is sometimes so high that damage can occur. This can be read in a corresponding article at PCGH. This probably applies to the Intel sockets LGA 1151 and 1200.
However, the report is dated January 4, 2016. PCGH also states that correct measurement is very difficult and that only the classification “too high” can be made roughly. A look at the current table of CPU coolers on the site shows that a Noctua NH-D15 or ThermalrightLe Grand Macho, for example, does not exceed the limit of 400 Newton.
Intel itself states 222 Newton but allows peak values of 712 Newton. The crooked values appear very precise, but only in the SI system of our usual units. Expressed in pound-force (the US unit), the limits are 50 and 160 pound-force respectively, and are more of a rough guide than a precise limit.
The cooler should always be removed before shipping
The manufacturer’s comments on this are interesting, as they always recommend dismantling the heat sinks during transport. Otherwise, they cite their test series as a reference, which is intended to prove the reliability and durability of the processor. We also found in the test that springs or similar mechanisms were almost always installed that limit the maximum pressure on the processor. The screws can also only be tightened to a certain point, so they cannot be tightened too much.
However, the question remains whether high pressure on the socket and thus the CPU has any effect on the cooling performance of the processor fan. So we simply placed the Be Quiet Pure Rock 2 CPU cooler on the base of our test system with thermal paste and did not screw it on. The procedure should not be imitated under any circumstances, but the processor did not heat up significantly more. The difference of almost 2 °C is harmless in any case. The powerful screwing primarily serves to securely fix the heat sink, which can sometimes be very heavy, during vertical installation.
In this sense, there is no connection between cooling performance and contact pressure. The excess heat will always take the path of least resistance and, even with a loosely fitting cooler, will pass through this contact surface with its high thermal conductivity. If there is any uncertainty regarding the contact pressure being too high, it is recommended to loosen the screws by half a turn or a full turn. The CPU cooler will remain firmly in place, but the pressure should remain low enough this way.
Setting options for the CPU cooler
After installation, the behavior of the fan can be additionally adjusted in the BIOS. The typically used curve keeps the fan quiet at low loads, but at high loads, the maximum speed is set for optimal cooling. For example, for a particularly quiet but slightly warmer system, the fan performance can generally be set to 50 percent. For a virtually silent PC, we even recommend reducing the performance to around 20 percent. With a large heat sink, this is enough to achieve high performance. This can be worthwhile for office and multimedia applications. But it wouldn’t be appropriate in a gaming PC.