The best thermal pastes for CPU and GPU according to their conductivity

You must take into account one thing is that in this article we will classify and select thermal pastes according to their conductivity, but there are other parameters to take into account such as its viscosity or the materials with which it is used. Is made . Although the thermal conductivity in the case of thermal pastes is directly related to the performance that can be expected from it, a better result is not necessarily obtained.

What is thermal conductivity and why is it important?

As you know, neither the IHS (the integrated heat sink) nor the contact surface of the heat sinks are completely flat, and therefore the contact between one and the other is not either. For this reason, it is necessary to place an inconstant material in between, so that it can accommodate these imperfections on the surface of the IHS and the base of the heat sink or water block.

The function of the thermal paste is very simple: to fill the spaces which remain between the surface of the two so that the contact is total. However, we put an intermediate layer between the heat sink and the IHS, and so it must have high thermal conductivity in order to be able to transfer the heat generated by the processor to the heat sink effectively and efficiently.

Therefore, thermal conductivity is the ability to transfer heat, although we can summarize it as the ease of changing the temperature over its entire surface. This quantity is expressed in W / mK which means watts of heat per meter Kelvin, and the higher this figure, the better the thermal transfer capacity of the thermal paste.

Other aspects to consider with thermal pastes

We must have other values ​​to take into account, as we said at the beginning, like the density or the viscosity of the product. Some manufacturers use the term “specific gravity” and others simply limit it by density, but in both cases it is expressed in g / cm³ or in grams per cubic centimeter. Another attribute that some manufacturers express is viscosity as well.

Density can often be determined empirically, simply by applying thermal paste, mounting the heat sink, and removing it again to observe the scatter pattern. Next, we’ll show you some examples of good and bad thermal pastes. In the image above, you can see poor quality thermal paste that is too liquid and has an exaggerated and irregular dispersion, so its effective thermal conductivity is weakened.

In the image below we will give you another example of bad thermal paste but for the opposite reason: it is too viscous and it is distributed very badly, leaving “globules” which again attenuate the thermal conductivity.

Finally, below these lines we give you an example of thermal paste with the correct viscosity and density, which facilitates its homogeneous dispersion on the surface to maximize thermal conductivity. You can see the pattern is similar to the first example, but here we can see that there are fewer voids where the contact will be bad.

The best thermal pastes according to their conductivity

Before we finally go through the ranking of the best thermal pastes according to their conductivity, we need to talk about which values ​​are considered good and bad, right? For example, the thermal conductivity of high quality paste is 8.5 W / mK, the thermal conductivity of copper is 385 W / mK, or that of aluminum is 205 W / mK.

You will realize that thermal pastes are actually not very good conductors of heat and this is exactly the reason why it is advisable to put a layer as thin as possible, since its objective is simply to fill the gaps. micro imperfections of the surfaces of the IHS and the radiator.

In any case, the higher the conductivity value, the better the performance we can expect from thermal paste, so we are going to take a look at some of the best known and best selling models to check which of them is the best. in this parameter, always keeping in mind mind It counts the rest of the aspects such as viscosity as we have indicated before.

We see that among all thermal pulp manufacturers, it is the manufacturer Thermal grizzly which occupies the first places. He also highlights that his Conductonaut model is in first position and with an abysmal difference from the second best, multiplying its thermal conductivity by 5, how can there be so much difference?

The main reason is that this thermal paste is composed of Liquid metal, with a eutectic alloy (mixture of several materials with a minimum melting point, so that even if it is metal, it is in the liquid state and not solid) of gallium and indium called EGaln. This alloy has the particularity of being liquid at room temperature and has a high thermal conductivity, even if it is true that Thermal Grizzly has created its own alloy (addition of tin among others) to create this Conductonaut.

The second position is occupied by the also famous Kyonaut from the same manufacturer, while the Prolimatech PK-3 occupies the third position. The most famous thermal pastes sold for their low price such as the Arctic Silver 5 or the MX-4 from the same manufacturer occupy positions 6 and 7 in this list, and curiously the thermal pastes from Noctua or Corsair are not only ‘they are positioned too well in this table compared to others (however, another parameter like durability comes into play here, since for example the Corsair TM30 is the longest of all and, according to the manufacturer, lasts several years without losing its properties).