Here’s everything you need to know about thermal paste: What it is for and how to use it to keep your processor cool.
If you’ve dabbled in PC building, you’ve probably heard of thermal paste. Among other names, this material is known as thermal grease, heat paste, CPU paste, thermal gel, and thermal interface material (TIM).
Whatever you call it, the proper application of thermal paste is critical to ensuring the proper operation of your CPU.
That is why it is critical to understand not only how it works but also how to use it correctly when working with a CPU.
When Should Thermal Paste Be Used?
When installing any type of cooling solution, the thermal transfer material is used. When most people think of thermal paste in the context of PC construction, they’re probably thinking of the process of installing a CPU cooler.
For example, when you buy a graphics card, the thermal solution is already built in. Unless you’re interested in aftermarket solutions such as custom liquid cooling, you shouldn’t have to worry about installing a cooler onto a GPU. With a CPU cooler, you can select the one you want, but you’ll almost always have to install it yourself.
Terms You Should Know
It’s important to define some of the terms we’ll be using to properly explain how thermal paste works.
Central Processing Unit (CPU)
– A computer’s information processing center. It executes all operational instructions and sends them to the computer’s other hardware.
If the computer is a body, the CPU is the brain, and it is critical to the operation of any PC.
Modern CPUs perform a large number of operations per second, which generates heat. A CPU must be properly cooled to operate at peak efficiency, typically with a cooling apparatus designed specifically for this purpose. This is when thermal paste comes into play.
Integrated Heat Spreader (IHS)
– The CPU’s metal “lid.” This acts as a heat sink, transferring heat from the processor to a CPU cooler while also protecting the processor inside.
This is the part of the CPU that remains exposed after being installed in a motherboard, and it is the surface to which thermal paste is applied.
CPU Cooler
– A device that keeps your CPU at optimal operating temperatures. CPU coolers typically use air or liquid to relocate heat generated by CPU operation.
Base-Plate
– The metal base of an air-cooler that attaches to the CPU’s IHS. This design allows heat to be transferred by convection to the heat sink’s fins, where it can then be redistributed by a fan.
Waterblock
– The device that connects 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
– is a silvery-gray substance that is applied to a processor before installing a cooling solution.
It enables the efficient transfer of heat from the processor’s IHS to the base plate or water block of the CPU cooler, which is designed to dissipate that heat.
What Is the Purpose of Thermal Paste?
Although the metal base of the CPU cooler and the CPU’s IHS appears smooth to the naked eye, these metal plates contain microscopic imperfections that can result in poor heat transfer.
Because the two surfaces aren’t completely in contact due to the imperfections, thermal paste fills in the air gaps, allowing for a more efficient heat transfer.
Simply put, thermal paste aids the performance of your CPU cooler, and a cooler CPU means fewer potential performance issues, such as throttling.
Important Preparations for Applying Thermal Paste
Most processors require some sort of thermal solution to operating at peak efficiency, but installing a CPU cooler in a PC is unique.
Every CPU cooler requires thermal paste, but many come with it already applied, making installation easier.
Check the bottom of the base plate or water block of your CPU cooler that connects to the CPU to see if you have a pre-applied paste. If the silver paste is already present, no additional paste is required during the installation process.
Before you begin, keep the following points in mind:
- Check to see if the CPU is clean and free of any old thermal paste. If there is, carefully remove the old paste from the CPU lid with isopropyl alcohol and a non-shedding microfiber cloth or paper towel before proceeding.
- Make sure the rest of your CPU cooler is ready to go before you start applying thermal paste. Check the instructions, make sure you’ve completed all of the steps up to attaching the CPU cooler and make sure you have all of the necessary tools on hand.
Situations to Avoid:
Use the proper amount of thermal paste, which should be about the size of a pea or a grain of rice. Inadequate amounts may not cover the necessary surface area to be effective. Too much reduces the paste’s efficacy because the metal surfaces are too far apart, and it also risks spilling out onto the motherboard during installation.
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It may be tempting to apply the thermal paste directly to the CPU.
We recommend letting the pressure from the installed base plate or water block do it for you. An incorrect manual application can cause air bubbles to form in the paste, reducing thermal conductivity.
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Air bubbles may also develop as a result of reusing paste.
As noted above, you should completely clear up all paste if an issue arises during the installation process that requires you to remove the CPU cooler.
Then, retry the installation procedure with a new program. You may reuse an application if you absolutely must for example, while you wait for replacement paste but keep in mind that this is only a temporary fix, and we advise a proper reapplication before using your CPU cooler for an extended time. 
Applying Thermal Paste: A Step-by-Step Guide
Before starting the installation procedure, we advise reading through the entirety of this section so you are prepared and aware of what to expect.
Before beginning, read all pertinent instructions.
This includes the ones that come with the thermal paste and CPU cooler. The process will go more smoothly if you are aware of the specifics of your brand of thermal paste and CPU cooler before you begin.
The IHS of the CPU’s core should be covered in thermal paste.
(You can skip this step if your cooler already has thermal paste applied.) A small amount, about the size of rice or pea grain, needs to be applied to the center of the built-in heat spreader.
Put in a CPU cooler.
When mounting your cooler to the mounting mechanism, apply light pressure from the top down to the CPU with the base plate or water block of the cooler in place. However, you don’t want to push so hard that you bend the motherboard or harm the CPU.
You just need enough pressure to prevent the cooler from moving and to spread the thermal paste properly. Keep the cooler in position while you fasten it to the motherboard in a diagonal arrangement, drawing an “X” with the screws (if you’re using one) to secure it.
To ensure uniform pressure, do not fully tighten the screws until all four have been secured. Instead, spin each one several times before moving on to the next.
Check your work again.
Once the CPU cooler’s base plate or water block is firmly mounted, double-check your work to make sure everything appears right.
Nowhere on the motherboard, including the borders of the CPU, should thermal paste be dripping. If there is, it indicates that you used too much paste and that you should rinse it off with alcohol before starting the procedure again.
Congratulations if everything appears to be in order and the cooler stays still when you touch it. You’ve finished this important step.
How Often Should Thermal Paste Be Replaced?
Most of the time, you shouldn’t have to reapply more frequently than every few years, but you should change your paste if you take your cooler out for whatever reason.
If you see that the temperature of your CPU is rising, you might want to think about applying thermal paste once more.
When in doubt, get advice from the producer of the thermal paste and heed their instructions.
Final thought
Although it may not get as much attention as gaming gear like the CPU or GPU, thermal paste is crucial to maintaining the performance of those parts.
To ensure you’re getting the best performance out of your CPU, learn how to apply thermal paste properly.
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