Published on

A guide on Thermal Grease/Paste

867 words5 min read
Authors
  • avatar
    Name
    Edwin Huang
    Twitter

Originally adapted from here.

Introduction

Thermal grease (or more commonly known as thermal paste) is used to spread heat generated from electronic components to a heatsink.

It is typically composed of different materials (depending on the brand) ranging from silicone to zinc oxide. While this usually doesn't change the paste's performance, there are some minor differences that accompany said materials. Some of these include thermal and/or electrical conductivity, temperature limits, durability, and the viscosity of the paste.

In regards to PC building and hardware, the amount of thermal paste needed in a given time is typically small. The reason for this is because thermal paste is designed to transfer heat from the electronic to something that dissipates said heat (usually a heatsink).

For this reason, thermal paste can typically be bought in small quantities (less than 1 gram).

picture showcasing thermal paste

A picture showing tubes and a container of thermal paste.

How it works

According to Intel,

Even though the metal base of the CPU cooler and the IHS (Integrated Heat Spreader) 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.

An illustration of what Intel is talking about is shown below:

heatsink

Thermal paste applied to a CPU heatsink

Things to know about

Most thermal pastes have a maximum shelf life of 2-3 years. This means that thermal paste should be replaced every 2-3 years because they won't be effective anymore.

  • For more information, click here.

Thermal Conductivity

  • Should be high (over 8.0 Watts per meter Kelvin)

Learn more about Watts per meter Kelvin here.

Electrical Conductivity

  • For the purpose of transferring heat from the electronic to the heatsink, the paste shouldn't have any electric conductivity because it may cause problems to the component that it's trying to transfer heat from.

    (Disclaimer: I couldn't find anything meaningful to support this claim, but it's a fairly logical guess.)

Temperature limits

  • Because it's tranferring heat, the general temperature limits should be around 150°C to 300°C. For reference, a CPU's temperature range would be around (50°C - 100°C)

Viscosity

  • For general cases, the paste should have a toothpaste-like consistency. The popular brands such as Cooler-Master or Arctic would fit this criteria. There is also a market for thicker/thinner thermal paste.

Applying methods

The Dot Method and the Line Method are the most common and easiest to do, but other methods are also listed below: These aren't ranked in any particular order.

MethodDescription
Dot Method(Probably) the most common way of doing things; easy to do and gets the job done.
Line MethodRelatively easy to do. Nothing much else to say.
X MethodMarks the spot.
Finger MethodA true hands-on experience.
Spiral MethodFor when you have too much thermal paste.
Sausage MethodLooks stylish.

This link illustrates the various forms of applying thermal paste.

In essence, there is numerous ways of applying thermal paste and while lots of them are fun to do, they don't really affect the paste's performance.

Other forms

Another form of thermal paste is thermal pads. Besides being relatively easier to apply, there really isn't too large of a difference.

thermalForms

A picture showing an thermal pad being applied on top of the CPU.

How to Apply it

There are several easy and straightforward steps:

  1. Make sure the CPU is clean and has nothing obstructing it

  2. Take the cap off of the thermal compound.

  3. In a way similar to injecting a syringe, carefully apply a pea-sized amount (2mm to 4mm) onto the center of the CPU.

  4. Carefully put the CPU fan's heatsink back onto the CPU.

Here is a video on it is done:

Terminologies Used

  • CPU: Central Processing Unit, essentially processing everything that goes through the computer. Often called the brain of the computer.
  • GPU: Graphics Processing Unit, displays graphics and other things to the console (or monitor).
  • Heatsink: The block of metal that spreads the heat from the CPU to itself. Also called Heat Spreader.

Sources

Discuss on Twitter • View on GitHub