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How to Apply CPU Thermal Paste to an Intel or AMD Processor

Learn all the essential details about thermal paste: Its purpose and the optimal method of application to ensure efficient cooling for your processor.

Applying thermal paste to a CPU

If you’ve ever explored PC building, you’re undoubtedly familiar with thermal paste, also known as thermal interface material (TIM). Thermal paste is crucial for the optimal functioning of your CPU. It is essential to understand both its functionality and the correct method of applying it when working with a processor. Installation methods are similar with both Intel and AMD processors.

What is Thermal Paste?

Thermal paste is a gray (usually its silver/gray) substance that is applied to the processor before installing a cooling solution such as an air cooler heatsink or liquid cooling waterblock. Its purpose is to facilitate the efficient transfer of heat from the Integrated Heat Spreader (IHS) of the processor.

Noctua Thermal Paste

Thermal paste, or thermal interface material, serves a crucial role during the installation of any cooling system. With computer assembly, the concept of thermal paste primarily relates to the process of installing a CPU cooler. However, when purchasing a graphics card, the thermal solution is typically already applied, eliminating the need for installing an additional cooler unless one seeks custom liquid cooling or aftermarket alternatives. Also, on motherboards, there are many different heatsinks on the various chips and there might even be a metal heatsink on the M.2 NVMe drives, in those instances there will be thermal paste, or a thermal pad installed to aid in the transfer of heat away from the chips and out of the computer chassis. If you are building a system yourself, you will need to install the thermal paste provided by the company that manufactured the CPU cooling solution.

If you don’t have any thermal paste and need to buy some, popular manufacturers include: Noctua, Arctic and Corsair.

Who is this information for?

We are a system integrator of custom desktop computers, primarily high-performance multiple monitor trading computers. The systems we sell are 100% fully built, tested and ready to use – no assembly or computer building knowledge is required. We like to write articles for customers that want to expand their knowledge and experience with computer hardware. This article is for our customers that someday might want to upgrade their CPU cooling solution or replace their thermal paste. We recommend our customers contact use prior to doing either, especially if the system is still under warranty. This article is also for DIY system builders that are building a system for the first time and want to learn all they can about various topics, and in particular about CPU thermal paste installation covered in this guide.

Understanding When Thermal Paste is Required

This article is designed to assist system builders in correctly applying thermal paste. If you have purchased a pre-built system from a company, the thermal paste would have already been applied. However, after several years of usage, it may become necessary to reapply thermal paste. If you find yourself needing to re-apply thermal paste to your current system, we recommend reaching out to the product manufacturer first. They can provide you with specific instructions on how to perform the process correctly and advise whether it would void your warranty, or if it’s even necessary in the first place.

What is an Integrated Heat Spreader?

The acronym IHS stands for Integrated Heat Spreader, which refers to the metal lid covering a CPU’s DIE. This component serves a dual function: safeguarding the processing silicon and facilitating the transfer of heat between the processor and the metal heatsink attacked to the surface of the IHS.

Integrated Heat Spreader on an Intel CPU

What is the Base Plate?

The base plate is the metal base of an air cooler heatsink. This heatsink base plate is affixed to the Integrated Heat Spreader (IHS) of the CPU. This design enables heat transfer via heat pipes to the fins of the heatsink, where it can subsequently be dispersed using fans attached to the heatsink. The image below shows the bottom of the Noctua NH-U12A Chromax Black air cooler.

Base Plate on a Noctua NH-U12A air cooler

What is the Waterblock?

Similar in concept to the base plate of an air-cooler heatsink. The waterblock is what attaches to the processor in a liquid cooling setup. The water pump is usually located in the waterblock that is installed on top of the CPU. The bottom of the waterblock is a smooth metal, such as copper, that makes direct contact with the CPU IHS. There will be a thin layer of thermal paste between the waterblock and the IHS. Most AIO (all-in-one) liquid cooling products will already have the thermal paste pre-applied to the waterblock.

Waterblock on a Corsair AIO liquid CPU Cooler

What is the purpose of thermal paste?

Despite appearing smooth to the touch, the metal base of the CPU cooler and the Integrated Heat Spreader (IHS) of the CPU actually possess tiny imperfections that hinder optimal heat transfer. These minute irregularities prevent the two surfaces from achieving full contact, creating gaps that impede heat dissipation. Thermal paste serves the vital purpose of filling in these gaps, facilitating a more efficient transfer of heat. In essence, thermal paste enhances the performance of your CPU cooler, leading to a cooler CPU temperature, which minimizes the risk of performance problems like thermal throttling.

Crucial Steps for Applying Thermal Paste

All modern processors require the installation of a CPU cooling product to ensure their proper operation. As processors are generating more heat than ever before, it is crucial to not only have an efficient cooling solution but also to correctly install it with the necessary preparations. While most CPU coolers do not come with pre-applied thermal paste, you will typically find a tube of thermal paste provided by the cooling solution manufacturer. However, there are instances where the thermal paste is already applied, such as with stock Intel or AMD coolers, and even many AIO liquid coolers that have the paste pre-installed on the waterblock. To determine if your cooler has pre-applied paste, examine the bottom of the base plate or waterblock that connects to the CPU. If you see the presence of paste, additional application during the installation process is unnecessary.

Some things to look out for:

  • If you’re dealing with a brand-new processor, make sure the surface is clean and any dust or oil from your fingers is wiped clean. Use a dry microfiber cloth to wipe off a new Intel or AMD CPU. If this is an older CPU and you are re-applying the thermal paste, you’ll need to wipe off the old paste. Use a microfiber cloth with isopropyl alcohol. You’ll need to be very careful and make sure you are taking proper precautions for static electricity by wearing an anti-static wrist strap. Remember to exercise utmost care during the process to avoid any potential damage to the CPU.
  • Make sure all prep work has been completed for the installation of the CPU cooler. Most coolers will have some type of brackets to attach that the heatsink will mount to. You don’t want to deal with installing all the brackets after the thermal paste has been applied.

How Much Thermal Paste is Required?

This is going to depend on the exact CPU you are installing, as some of the more modern ones are a little bigger and require slightly more. A general rule has always been to use a size roughly equivalent to a grain of rice or a small pea. Basically, you’ll be putting one small drop directly in the middle of the processor. Please refer to the instructions provided by your CPU cooling solution, often they will tell you how much of their thermal paste should be applied.

Example: Intel LGA115x with the Noctua NH-U12A CPU Cooler

With this processor and socket Noctua suggests a small drop roughly 3-4mm in diameter, placed directly on the center of the processor. This is with their NT-H1 thermal paste included with the cooler. The LGA20xx instructions are nearly identical for this cooler except they recommend 4-5mm in diameter of thermal paste since those processors are slightly larger. AMD processors will be the same with 4-5mm of thermal paste. Consult the installation instructions with the cooler in case any of the requirements have been modified or changed entirely.

Showing processor thermal paste

Exercise Caution – excessive thermal paste reduces heat conductivity and impairs cooling efficiency. It is crucial to be cautious when applying thermal paste. Over-application can result in diminished heat conductivity between the Integrated Heat Spreader (IHS) and the heatsink, decreasing the overall cooling performance.

Example: Intel LGA1700 (LGA17xx family) with the Noctua NH-U12A CPU Cooler

Since these processors are larger the thermal paste application is a little bit different. You’ll apply 5 small dots, one large one in the center 3-4mm in diameter and 4 dots near the corners 2mm in diameter.

Thermal paste pattern on a Noctua LGA1700 processor installation

Read all instructions and documentation before you begin.

While we provided a couple quick examples, it’s important to note that these do not encompass all installation scenarios. Each CPU cooler and thermal paste variant is unique, and manufacturers provide instructions regarding the appropriate amount and application method for their specific cooler. While we can’t possibly cover the countless models of coolers available, installation processes tend to be generally similar across most CPU cooling solutions.

No matter what, refer to the instructions provided by the manufacturer of the thermal paste and/or the CPU cooler manufacturer. They are the ultimate authority on how to apply their product. As always, there is a bit of contention online about the best pattern or way of applying the paste.

Things to Steer Clear of

  • Resist the urge to touch the thermal paste or smear it with your finger. You need to rely on the pressure exerted by the heatsink base-plate or waterblock during installation for proper paste distribution. Trying to spread it yourself can result in the formation of air bubbles within the paste, or dead spots where no thermal paste exists under the heatsink base plate. The idea here is that the small pea sized drop of paste will uniformly spread outward toward the edges and corners, and it works really well, trust us!
  • This is stating the obvious – don’t use too much or too little thermal paste. Use only the required amount.
  • Don’t reuse old thermal paste. It’s probably dried out anyway. Old paste should be wiped off the CPU and base plate or waterblock.
  • After setting the cooler on the IHS and thermal paste don’t slide it around, you want it to just compress down on the CPU. You need to center the heatsink base plate or waterblock so it’s roughly where it needs to be to start attaching it to the mounting solution provided.

Should You Replace Old Thermal Paste?

The answer to this is a little subjective. If your computer CPU is cooling fine under load, then it’s ok to just leave things alone. We recommend contacting your system integrator (manufacturer) if you purchased a pre-build system, they can provide guidance to you about applying new thermal paste. You could also contact the manufacture of the thermal paste and ask them how long their product is intended to last under normal usage conditions. Some recommend replacing thermal paste every few years, although it’s not a strict rule.

Conclusion

While not the most riveting subject when discussing computer hardware, thermal paste plays a crucial role that should be comprehended by those assembling their own systems. If you’re upgrading the cooler on an older system or replacing old paste, it’s valuable to grasp the proper installation technique for thermal paste. We hope you’ve learned something from our article, thanks for reading!