The liquid metal of PlayStation 5 cooling, explained: why Sony chose it for its next-gen console

Sony has an outstanding debt with users. The cooling system that it has implemented in both PS4 and PS4 Pro is very noisy at times of maximum workload. In fact, it becomes annoying. The latest PS4 Pro reviews have toned down this issue slightly and lowered the noise level by a few decibels, but not enough at all to solve this handicap in a fully satisfactory way.

Many users were looking forward to having more information about the PS5 cooling system to be able to intuit if Sony had managed to solve this problem in its new generation console. The video game forums are full of comments from fans who have raised concerns, and thankfully Sony has responded . And it is that a few hours ago he published a video in which one of those responsible for the mechanical engineering department completely disassembled the console and revealed what its cooling system is like .

There is no doubt that we cannot be sure if this solution is really effective and if it is silent or not until we have the console at home, but the information that Sony has revealed confirms that they have taken great care in the design of the cooling of PS5 . On the other hand, it is what he played.

The massive 120 x 45mm turbine-style fan and gigantic copper-rich heatsink look really good, but the most striking element of this cooling system is the liquid metal that acts as an interface between the SoC core and the heatsink base. It is very likely that this component is largely responsible for the cooling capacity of this console, and for this reason it is worth getting to know it a little better.

TIM: what is it and why is it so important

The acronym TIM comes from the name Thermal Interface Material in English , and describes the material used as a thermal interface between a chip and the heatsink that is responsible for cooling it. If we stick to microprocessors and graphics processors, which are the chips that tend to dissipate the most energy in the form of heat, the TIM acts as an interface between the encapsulation that covers the CPU core and the base of the heatsink.

The mechanism that explains how the transfer of thermal energy between two solid elements takes place is known as conduction, and its efficiency is greater when the contact surface between the two objects is maximum

Manufacturers of semiconductors and heatsinks tend to strive to ensure that the contact surface between these components is homogeneous and as polished as possible because it is crucial to maximize it to optimize the transfer of energy in the form of heat between them. However, no matter how well resolved the metal is, it has small imperfections that are very difficult to correct even if they are machined very precisely.

The mechanism that explains how the transfer of thermal energy between two solid elements takes place is known as conduction , and its efficiency is greater when the contact surface between the two objects is maximum. The problem is that if these two surfaces are not completely homogeneous, which in this context they never are, those small imperfections end up being occupied by tiny air pockets, which is a poor conductor of thermal energy.

This deficiency, precisely, justifies the existence of the TIM , which in practice is a thermal putty or paste that is placed between the surfaces of the CPU or GPU housing and the heatsink. In this way, the thermal paste forms a thin film of material that fills in the imperfections of the metal surfaces in contact and favors the conduction of thermal energy, which is precisely what we are looking for.

TIM is usually a thermal paste that is placed between the surfaces of the CPU or GPU housing and the heatsink.

Each thermal paste manufacturer has its own recipe, so not all putties have the exact same composition. Some use aluminum oxide; others are boron nitride, zinc oxide or aluminum nitride, and a few, the more sophisticated, contain silver particles in suspension. The composition of a thermal paste is important because it determines its thermal conductivity index , a parameter that measures the ability to transport energy in the form of heat that a material has.

The heat conductivity of metals is significantly higher than that of non-metallic materials, such as thermoplastics or wood, which is why it is so important to introduce metallic particles into thermal paste. In this way we are able to increase the energy transport capacity in the form of heat of the compound, but we also run the risk of increasing its electrical conductivity , and this could lead to problems if the putty comes into contact with any electrical or electronic component of our computer.

Liquid metal is a good choice, but difficult to handle

As we have just seen, the thermal conductivity index of thermal pastes is higher than that of air, which is a good thermal insulator. Even so, the heat conductivity of these putties is much lower than that of metals, so the ideal TIM would be one that has a heat conductivity coefficient as close as possible to that of metals. In that case, why not use a liquid metal as the interface between the CPU or GPU package and the heatsink? In this way we maximize the contact area between metal surfaces, we evacuate the air and we have a high heat transport capacity .

Using a liquid metal alloy like TIM is a very attractive strategy due to its ability to conduct heat, but it poses a challenge: it is crucial to prevent this component, which also has the ability to conduct electricity, from coming into contact with other elements. of the team. Liquid metal compounds used in electronic applications for the purpose of promoting the transport of thermal energy usually use an alloy of gallium, indium, and tin known as galinstane.