Heatsinks - everything you need to know 【complete guide】

In the market we find increasingly powerful processors and graphics cards, requiring proportional heatsinks in performance. If it were not for the use of them, computers as such could not work, at least desktop or laptop computers since their main components would burn without remedy.

In this article we will try to get to know in depth computer heatsinks, their elements, the fundamentals of operation and the types that exist. If you are thinking of buying one of these, don't miss this item, so let's get started!

Index of contents

What is a heatsink

The heatsink is the element that is responsible for dissipating or removing the heat generated by an electronic component due to use. There are many types of heatsinks, such as air, liquid cooling, or even direct convection in components immersed in a non-conductive liquid. But the ones we will cover here are the air coolers, the most common to connect and the ones used by the most users.

In fact, in a computer we not only find a heatsink, we may think that heatsink is only the block that is on top of the CPU or on the graphics card, but nothing is further from reality. Other components such as the motherboard chipset or the VRM of the same, also need heatsinks.

Precisely this last element has gained considerable prominence in recent times. The VRM is the processor's power supply system, and as such it must send a large amount of current for it to work, we are talking between 90 and 200 amps (A) at about 1.2-15V. MOSFETS are transistors that regulate the current that is sent to the CPU and memory, so they get very hot. We also find heatsinks in the power supply for the same reason, and in general in any chip that operates at a high frequency.

How it really works: physical foundation of heatsinks

It all starts with the way an electronic component generates heat, which is called the Joule Effect. It is a phenomenon that occurs when electrons are moving in a conductor. Consequently, an increase in temperature will occur due to the kinetic energy and the collisions between them. The more energy intensity, the greater flow of electrons will be in the conductor, and, consequently, the more heat will be released. This is extensible to silicon chips, inside which a large number of electrons condense in the form of electrical impulses.

We can see this phenomenon perfectly in this thermal capture. When a PC is consuming a large amount of power, even conductors increase in temperature.

That said, the heatsink is nothing more than a metal block made up of hundreds of fins that is in direct contact with the chip through a thermal paste. In this way, the heat generated by the chip passes to the heatsink and from it to the environment. Generally, one or two fans are placed above the heatsinks to help remove heat from the metal. In essence, two mechanisms of heat exchange intervene:

• Conduction: it is the phenomenon by means of which a hotter solid body passes its heat to a colder one that is in contact with it. That occurs precisely between the CPU's IHS and the heatsink. Then we will see that there is some thermal resistance between them. Convection: Convection is another phenomenon of heat transfer that occurs only in fluids, water, air or steam. In this case, air reaches the fins of the heatsink, preferably at high speed so that it is able to take more heat from the hot fins of the heatsink.

Magnitudes to know if a heatsink is good

Seen the operation from the technical point of view, we will still have to know the main magnitudes involved in a good heatsink. Although it is true that many of them are not reflected in the specifications, for the most curious they will be interesting.

• TDP: The TDP is undoubtedly the most important parameter of a heatsink, as it is very representative. We call TDP (Thermal Design Power) the amount of heat an electronic component is expected to generate when it is at its maximum load. This parameter appears on processors and heatsinks and has nothing to do with the power consumption of the electronic component itself. So the processor is set up to support maximum TDP, so a heatsink must have the same or more for the CPU to work safely. TDP CPU <TDP Heatsink, always. Conductivity and resistivity: conductivity is the ability to transport heat that a body or substance has. And resistivity, because just the opposite, the resistance it presents to conduct heat. Conductivity is measured in W / mK (Watt per Meter Kelvin) and the more the better. Thermal resistance: thermal resistance is the phenomenon that opposes the passage of heat from one element to another. It is just like an electrical resistance, the bigger it is, the harder it will be for heat to pass. In a refrigeration system many thermal resistances intervene, for example, the contact of the CPU and the heatsink, the contact between the encapsulation and the cores, etc. Therefore, it is about putting elements with high conductivity, to avoid these resistances. Contact surface: The contact surface is not something that is given in the specifications, as it is part of the design of the heatsink. If we were to face a plate with a Noctua D15, which one would you say have more contact surface? Well the sink without a doubt. This parameter measures the total area that will be bathed by air. The more fins, the greater exchange surface, since they all have two faces, one after the other multiplied by hundreds of them. Air flow and pressure: these parameters are relative to the fans. Air flow is the amount of air that a fan sets in motion, and is measured in CFM, while static pressure is the force with which air strikes the fins, and is measured in mmH2O. In a heatsink we want the maximum possible pressure with a high flow.

Components and parts of heat sinks

After seeing the parameters involved in the operation of a PC heatsink, it is no idea to know what elements are part of it. Or rather, how a worthwhile heatsink is built. In addition, we will see the elements that intervene just after the DIE or processor cores.

IHS

The IHS, or Integrated Heat Spreader, is the encapsulation of the CPU. Here it all begins, since it is the first element that is in contact with the processor cores, which really generate the heat of the electronic component. This package is made of copper, and the most powerful processors are directly soldered to the DIE to eliminate thermal resistance to a minimum.

This ensures that all possible heat passes in the best conditions to the other dissipation elements. There are chips that do not have this encapsulation, such as GPUs, in them, the heatsink makes direct contact with the DIE of the cores with the help of thermal paste, so the transfer is more efficient. The process of removing the IHS and putting the heatsink in direct contact with the DIE is called Delidding. With liquid metal based thermal paste you can improve temperatures by up to 20⁰C or more.

Thermal paste

The element with the highest thermal resistance in the heatsink assembly. It is very important to have a very good thermal pass in powerful chips, since its conductivity will be higher. The function of the thermal paste is to improve as much as possible the connection between IHS or DIE and the cold block of the heatsink.

Although it seems to us that a block is very well polished, microscopically the contact is not perfect as they are solid, so an element that physically links them is needed for the heat conduction to have an effect.

In the market we have three types of thermal paste, those of ceramic type, generally white, those of metallic type, almost always gray or silver or those of liquid metal that seem, well, liquid metal. The metallic ones are the most common, with a very good performance / price ratio and reaching conductivities of up to 13 W / mK. Liquid metal ones are normally used for Delidding, and have conductivities of up to 80 W / mK.

Cold block

The cold block is the base of the heatsink, which contacts the processor or electronic chip. It is typically larger than the IHS itself, to ensure maximum heat reception and transfer.

A good heatsink always has a base made of copper. This metal has a conductivity of between 372 and 385 W / mK, being only surpassed by silver and other more expensive metals. Note the difference between this value and that offered by a thermal paste.

Heat pipes

We are assuming that we are evaluating a good performance heatsink, and these always have heat pipes or heatpipes. Like the cold block, they are made of copper, or nickel-plated copper.

Their function is very simple but very important, to take all the heat from the cold block and carry it to the fin towers above it. Sometimes it is done in a very visual way with the heatpipes separating the block from the towers, and others are integrated into the set, as is the case with the Wrait Prisms of the AMD.

Finned tower or block

After the two previous elements, we have the heatsink itself. It is a rectangular or square tower shaped element provided with an incredible number of fins joined together by heatpipes or other fins. They are always made of aluminum, a metal lighter than copper and with a conductivity of 237 W / mK. The heat expands in all of them, to transfer it by convection to the air that is in contact with its surface.

Fan

We believe it is also part of the heatsink for doing the important job of creating high-speed airflow so that convection, instead of being natural, is forced and removes more heat from the metal.

The current heatsinks usually carry almost all one or two fans, although they do not necessarily have a standard size as it happens in those that are sold separately for the chassis.

Types of heatsinks

We also have different types of heatsinks on the market. Each of them is oriented to a different functionality, if we can also classify them in different ways.

Passive heatsinks

A passive heatsink is one that does not have an electrical element working on it to help it remove heat, for example a fan. These heatsinks are not usually used for processors, although they are for chipsets, or VRM. They are simply finned aluminum or copper blocks that expel heat by natural convection.

Active heatsinks

Unlike the others, these heatsinks have an element in charge of maximizing the heat exchange with the environment. The fans mounted on them have PWM or analog current control for various revolutions per minute depending on the temperature of the processor. Precisely for this reason, they are active heatsinks.

Tower heatsink

If we look at its design, we also have several types, and one of them is the tower heatsink. This configuration is based on a cold block provided with a large finned tower not necessarily attached directly to it, but by heatpipes. We can find heatsinks of one, two and even four towers with extravagant design. Its measurements are usually around 120 mm wide and up to 170 mm high, designed more than 1500 grams.

A characteristic of these is that the fans are placed vertically with respect to the plane of the motherboard. This does not cancel the fact of having models with them horizontally.

Low profile heatsinks

Unlike the previous ones that have a considerable height, these bet with very low configurations for narrow chassis or reduced spaces. It can be considered that they have a tower, although it is horizontal. They even have fans sandwiched between this tower and the cold block.

Unlike the previous ones, the fans are always placed horizontally and parallel to the plane of the base plate, expelling air vertically or axially.

Blower heatsinks

Blower coolers are used for graphics cards and other components in the form of expansion cards. Currently we also find similar configurations for high-powered chipsets like the AMD X570. We also find them in HTPC or NAS, which due to their small space are the most effective.

They are characterized by having a centrifugal fan that absorbs air and expels it on the finned block parallel to the fins. They are generally worse potion than previous heatsinks.

Stock heatsinks

It is not a design as such, but they are the heatsinks that the manufacturer of the processor includes in its purchase pack. There are some of very good quality like those of AMD, and others very bad like that of Intel.

Liquid refrigeration

These systems are made up of a closed circuit of distilled water or any other liquid that can be used. This liquid remains in continuous movement thanks to a pump or a tank provided with a pump so that it passes through the different blocks installed on the hardware to be refrigerated. In turn, the hot liquid passes through what is essentially a radiator-shaped heat sink, more or less large, provided with fans. In this way, the liquid cools down again, repeating the cycle indefinitely while our equipment is running.

Laptop heatsink

In a special category we can put the heatsink of laptops, systems that are worth seeing in action because some are really worked.

These heatsinks are quite special, because they make the most of the conduction phenomenon. Thanks to cold blocks installed on GPUs and CPUs from which long thick bare copper heatpipes come out, bringing heat to the dissipation zone. This zone is made up of one, two or up to four centrifugal fans that blow heat out between small finned blocks.

What to take into account for its assembly

Mounting a PC heatsink is not too complicated, and there are not many factors to take into account when mounting one, for the sole purpose of its compatibility and measurements.

We refer to the compatibility with the platform that we have on our PC. Each manufacturer has its own sockets where to install the processors, so the grips and size are not the same. For example, Intel currently has two: the LGA 2066 for the X and XE Workstation ranges, and the LGA 1151 for the desktop Intel Core ix. On the other hand, AMD also has two, the AM4 for Ryzen, and the TR4 for Threadripper, although these almost always go with liquid cooling. In any case, available non-stock heatsinks always come with mounting systems compatible with all sockets.

Regarding the measures, there are two that we must take into account. On the one hand, the height of the heatsink, which we must compare with the admissible height with our chassis, going to its specifications. On the other hand, the width and space available for RAM memory. Large heatsinks take up so much that they get on top of RAM, so we must know what profile they support.

A third important element is knowing if the heatsink comes with a thermal paste syringe or already pre-installed in the block. Most do bring it, but it is not necessary to make sure in case we have to buy it separately.

Advantages and disadvantages of heatsinks

As we did in the article on liquid cooling, here we will also see the advantages and disadvantages of using heatsinks.

Advantage

• High PC compatibility Sizes for almost every taste Cheap and effective even for powerful processors Few cables and easy installation More reliable than liquid cooling, no fluid or pumps that can fail Simple maintenance, just clean up dust

Disadvantages

• For processors with more than 8 cores they can come right They take up a lot of space and are heavy Limitations for the height of the chassis and height of the RAM Aesthetic not very refined

Conclusion and guide to the best heatsinks for PC

We finish this article in which we discuss in depth the issue of heatsinks. Above all, we have focused on its operation and its fundamentals of construction and components, since it is one of the topics less generally treated.

A good heatsink can perfectly supply the need for liquid cooling, since there are such brutal configurations on the market as the Noctua NH-D15s, Gamer Storm Assassin, or the huge Scythe Ninja 5 and Cooler Master Wraith Ripper. Now we leave you with our guide.

Guide to the best heatsinks, fans and liquid cooling for PC

What heatsink do you have on your PC? Do you prefer air coolers or liquid cooling?