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Here’s all the info you need when it comes to thermal paste: What it’s for, and how to apply it to make sure your processor is properly cooled.

Posted by Qifeng Liang · November 16, 2021

If you’ve delved into the world of PC building, you’ve no doubt heard about thermal paste. This material is also known as thermal grease, heat paste, CPU paste, thermal gel, and thermal interface material (TIM), among other names. Whatever you call it, the correct application of thermal paste is an important part of ensuring your CPU is operating properly.

That’s why it’s important to know not only how it works, but also how to correctly apply it when working with a CPU.

When Do You Need to Apply Thermal Paste?

Thermal transfer material is used when installing any cooling solution. When people think about thermal paste in the context of building a PC, they’re probably referring to the process of installing a CPU cooler. When you buy a graphics card, for example, the thermal solution is already integrated. You don’t usually have to worry about installing a cooler onto a GPU, unless you are interested in aftermarket solutions like custom liquid cooling. With a CPU cooler, you have the option to choose the one you want, but that means you’ll usually need to install it yourself.

Terms You Need to Know

In order to properly explain how thermal paste functions, it’s worth defining some of the terms we will be using.

Central Processing Unit (CPU) - The information processing center of a PC. It executes all operational instructions and sends instructions to the other hardware in the computer. If the computer is a body, then the CPU is the brain, and it is absolutely critical to the functioning of any PC. Modern CPUs execute a high volume of operations per second, and this generates heat. In order for a CPU to operate at peak efficiency, it needs to be properly cooled, usually with a cooling apparatus designed just for this purpose. This is where thermal paste becomes important. If you'd like to learn more about how a CPU is made, you can read more about the manufacturing process.

Integrated Heat Spreader (IHS) - The metal “lid” of the CPU. This serves as a heat sink designed to distribute heat from the processor itself to a CPU cooler, as well as provide protection to the processor inside. This is the part of the CPU that is still exposed after being installed in a motherboard, and is the surface to which you apply thermal paste.

CPU Cooler - The device that keeps your CPU running at optimal temperatures. CPU coolers usually use air or liquid to relocate the heat created by the operation of the CPU.

Base-Plate - The metal base of an air-cooler that attaches to the IHS of the CPU. This design allows the transfer of heat through convection to the fins of the heat sink, where it can then be redistributed with a fan.

Waterblock - The apparatus that attaches to the IHS when using an All-in-One (AIO) liquid cooler or a custom cooling loop. It transfers heat from the IHS to the heat transfer fluid, which then relocates that heat to be redistributed by fans at a radiator.

Thermal Paste - A silvery-gray substance that you apply to a processor before installing a cooling solution. It allows for an efficient transfer of heat from the IHS of the processor to the base plate or water block of the CPU cooler that is designed to dissipate that heat.

Why Do You Need Thermal Paste?

Even though the metal base of the CPU cooler and the IHS of the CPU look smooth to the naked eye, these metal plates have microscopic imperfections that can result in poor heat transfer. The two surfaces aren’t in full contact due to those imperfections, so thermal paste fills in those air gaps, allowing for a more efficient transfer of heat.

Simply put, thermal paste helps your CPU cooler do its job, and a cooler CPU means less potential performance issues, such as throttling.

Important Preparations for Thermal Paste Application

Most processors require some sort of thermal solution to properly operate at peak efficiency, but the process of installing a CPU cooler in a PC is unique.

Every CPU cooler needs thermal paste, but many have it pre-applied, which simplifies the installation process. To find out if you have pre-applied paste, check the bottom of the base plate or water block of your CPU cooler that attaches to the CPU. If the silver paste is already there, you don’t need to add any more during the installation process.

A few things to keep in mind before starting:

Make sure that the CPU is clean, and that there isn’t any old thermal paste on it. If there is, carefully remove the old paste from the lid of the CPU with isopropyl alcohol and a microfiber cloth or paper towel that doesn’t shed, and let it dry before continuing.
Before you start applying the thermal paste, make sure the rest of your CPU cooler is ready to install. Consult the instructions, ensure that every step has been completed up to attaching the CPU cooler, and make sure you have any necessary tools close at hand.

Situations to Avoid:

Make sure to use the correct amount of thermal paste, which is roughly the size of a pea or a grain of rice. An insufficient amount might not cover the surface area needed in order to be effective. Too much reduces the efficacy of the paste, due to the metal surfaces being too far apart, and also risks spilling out onto the motherboard during installation.
It might be tempting to spread the thermal paste onto the CPU yourself. We recommend letting the pressure from the base-plate or waterblock being installed do it for you. Incorrect manual application can cause air bubbles to form in the paste, which can negatively impact the thermal conductivity.
Reusing paste can also cause air bubbles to form. If a problem occurs during the installation process and you have to remove the CPU cooler, you should completely clean off all paste as mentioned above, then try again with a fresh application. If you absolutely need to reuse an application — while waiting for replacement paste, for example — you can, but keep in mind this is a short-term solution, and that we recommend a proper reapplication before long-term use of your CPU cooler.

How to Apply Thermal Paste - Step by Step

We recommend reading through this entire section before beginning the installation process, so you know what to expect, and can plan ahead.

Read all relevant instructions before starting. This includes those that come with your CPU cooler and thermal paste. Every brand of thermal paste and CPU cooler is a little different, and knowing the particulars of yours before starting will help the process go smoother.
Apply thermal paste onto the center of the CPU’s IHS. (If you already have thermal paste pre-applied on your cooler, you can skip this step.) You only need to apply a small amount — roughly the size of a grain of rice or a pea — onto the center of the integrated heat spreader.
Install CPU cooler.Use light, top-down pressure to place the base-plate or waterblock of your cooler onto the CPU, and hold that pressure while attaching the cooler to the mounting mechanism. You’ll want to use enough force to keep the cooler from sliding, and to evenly distribute the thermal paste, but you don’t want to push hard enough to bow the motherboard or damage the CPU. Keep the cooler in place as you attach it to the motherboard in a diagonal pattern, securing the screws (assuming you are using a screw mechanism) as if you were drawing an “X” with them. Do not fully tighten the screws until you have attached all four, then turn each a few times before moving on to the next in order to ensure even pressure.
Double-check your work.Once the base-plate or water-block of the CPU cooler is firmly attached, check your work to make sure everything looks correct. There shouldn’t be any thermal paste spilling over the edges of the CPU, or anywhere on the motherboard. If there is, it means you used too much paste, and should clean it off with alcohol and start the process again. If everything looks clean and the cooler doesn’t move when you touch it, then congratulations! You’ve completed this critical step.

Replace Thermal Paste?

In most cases, you shouldn’t need to reapply more than once every few years, though you should replace your paste if you remove your cooler for any reason. You may also want to consider reapplying thermal paste if you find your CPU temperatures are climbing.

If in doubt, consult the thermal paste manufacturer, and follow their recommendations.

Stay Cool Out There

Thermal paste may not be discussed as frequently as gaming hardware like the CPU or GPU, but it is an essential part of keeping those components functioning at their best. Knowing how to properly apply thermal paste can help to make sure you’re getting the best performance from your CPU.

Household substitutes for CPU thermal paste

Posted by Qifeng Liang · September 07, 2021

Thermal transfer compound, colloquially known as “thermal paste,” is arguably one of the most crucial, yet frequently overlooked, components of PC assembly. It’s not uncommon to forget to purchase a tube of inexpensive Arctic Silver compound after spending hundreds of dollars or euros on every other component involved in the build. If you’re desperate enough to get things going, there are household alternatives that can serve as a temporary substitute for commercial-grade thermal paste.

Thermal paste, or some oily thermal interface material, is necessary because it fills in the microscopic imperfections that otherwise trap air particles between the CPU and the heatsink, preventing the CPU from properly cooling. Heat radiates outward from the CPU to the heatsink, before eventually making its way to a fan where it disperses; but, since air is a notoriously poor conductor of heat, an outside element is needed to bridge the gap between the two components.

Very often, assemblers and computer repairers do not have thermal paste available. It is a fundamental component because it helps cooling the CPU temperature down, lowering the thermal resistance between the microprocessor and the heat sink.

Typically, PC-grade thermal paste supplies the necessary bridge, but most oily household substances could temporarily suffice. A quick Internet research reveals that many users have already taken it upon themselves to test out a variety of substances for use, including vegemite, Nutella, toothpaste, and American cheese.

Jorgen Elton Nilsen, of the Norwegian tech site Tek.No, tested all of his substances using an Innovatek Kühlertester KT-3 simulator, an industry-grade heater for analyzing the cooling capacity of air and water cooling systems. Devices like Innovatek are better suited for this task, as it’s difficult to standardize the heat output of a CPU solely through software. One can’t simply activate the maximum heat output by running a 3D-rendering demo because of the inherent bias: there’s no way to determine how much of the CPU’s specified maximum power rating is used up by the software.

Instead, Nilsen set up his Innovatek Kühlertester KT-3 with a heat spreader and an Asus Triton 77 heatsink mounted on top of the CPU and proceeded to test toothpaste, yellow cheese, hair wax, moisturizing cream, butter, banana, and paper at intervals of 15 minutes under a 90-watt load.

The results will surprise you. In order from the most thermally conductive to the least:

Butter 53.2°C

Moisturizing cream 54°C

Hair wax 56°C

Toothpaste1°C

Banana 58°C

Paper 67.2°C

Yellow cheese 67.9°C

Taken at face value, it appears that the butter and the moisturizing cream are the best short-term solutions, but truthfully, both liquefied before the allotted 15-minute time frame came to a close. Considering that a motherboard sits beneath a CPU inside a computer, the liquefied oil runs the risk of spilling over onto underlying electronics.

The best solutions turned out to be hair wax and toothpaste, which exhibited a relatively low temperature without completely drying out and cracking.

If you’re impatient or under a tight deadline and need to squeeze in a few hours of extra work, consider toothpaste or hair wax when nothing else is available. When the time comes to replace it with actual thermal paste, use a sharp edge to remove the dried-up compound before applying a small amount of isopropyl alcohol to a microfiber cloth and gently scrub off any excess particles. Suffice it to say, computer-grade thermal paste eventually dries up as well, needing to be periodically cleaned off and reapplied.

How to use the thermal grease at a better way

Posted by Qifeng Liang · July 14, 2021

Introduction

Whenever you install a heatsink on a CPU or a video card, you always have to apply thermal paste. It is very crucial to the performance of the heatsink. You could get a very high-end heatsink, and without thermal paste, it will fail to work in the way it was designed too.

What is thermal paste and what does it do?

Thermal paste is a very high heat conductive paste that is used between two objects (usually a heatsink and a CPU/GPU) to get better heat conduction. It fills in all those microscopic imperfections on the heatsink and CPU/GPU that can trap air in them and cause a loss in the heatsink’s performance. Air is a very poor conductor of heat. Thermal Interface Materials (TIM) can be up to a 100 times greater conductor of heat than air.

However, thermal paste is not near as good of a conductor as copper. Thus, too much thermal paste will hinder a heatsink’s ability to cool properly.

This is an exaggerated view of what these microscopic imperfections would look like. All the white area would represent the air pockets, and this is what the TIM would fill in. It wouldn't be such a gap like this, but this just an example to give you a rough idea of what it would look like.

If you could have a perfectly flat heatsink base, and CPU, you would not need thermal paste. But it is impossible to do so, and that’s why we need thermal paste.

Types of thermal paste

There are essentially three types of thermal pastes:

Metal based
Ceramic based
Silicon based

Metal-based TIM’s are the most popular as they have the best performance out of the three. These pastes have lots of little metal particles in the grease that have a high thermal conductivity. One disadvantage of this type of paste is that it is also electrically conductive as well, which can cause a problem, more on this later.

Ceramic-based TIM’s are also a popular solution that doesn’t perform quite as well as metal-based pastes, but the difference is minimal (1-3C). These consist of some form of thermally conductive material with lots of little ceramic particles. The advantage of ceramic-based pastes is that they do not conduct electricity.

Silicon-based TIM’s are usually what thermal pads that come on stock heatsinks are made of. These work well, but nowhere near to what other pastes will. Usually they come with cooling kits.

There are also thermal epoxies, these are basically the same thing as regular grease, but are actually used to permanently attach the heatsink. They are not recommended for most cases, but in some they are of course. One main example for a use of an epoxy is, attaching heatsinks to video memory. Most of the time you use thermal pads that don’t perform very well, so an alternative is thermal epoxy. But the disadvantage is, that most of the time you will not get the heatsinks off once they are put on.

What can be tried to get epoxied heatsinks off is to put the video card in the freezer before trying to remove the heatsink. The low temperature will make the epoxy brittle, so it goes off easier.