Thermal Grease

Thermal paste, also known as thermal compound or thermal grease, is a substance used in computer systems to improve the thermal conductivity between a heat-generating component and its heat sink. Its primary purpose is to fill in microscopic gaps and imperfections between the mating surfaces of the component and the heat sink, which helps to maximise the transfer of heat from the component to the heat sink. It's commonly used for CPUs, GPUs, chipsets, and other electronic components. Shop a range of thermal greases with different thermal conductivity levels, dispensing formats, and operating temperature ranges at RS New Zealand.

How Thermal Grease Works

The surfaces of a processor and a heat sink are never perfectly smooth. Even surfaces that appear flat contain microscopic imperfections, allowing air pockets to form at the contact points. Since air is a poor conductor of heat, these gaps reduce thermal efficiency. Thermal grease fills those imperfections and creates a more direct thermal pathway between the two surfaces. It is typically made from thermally conductive particles suspended in a carrier compound, with only a small amount applied before mounting the heat sink.

Types of Thermal Grease & Thermal Paste

Not all thermal greases perform the same way. Different formulations suit different applications, performance requirements, and installation environments. Here is a breakdown of the main types available:

Standard Thermal Grease / Paste

Standard thermal grease, also referred to as thermal paste, is the most widely used option for everyday computer builds. Typically silicone or zinc oxide-based, it offers reliable thermal performance for most consumer CPUs and GPUs operating within normal temperature ranges. It is straightforward to apply and widely available, making it a practical choice for general maintenance and assembly work.

High-Conductivity Thermal Grease

High-conductivity thermal grease is formulated with metallic or ceramic particles to deliver superior heat transfer performance. It is commonly used in demanding applications such as high-performance gaming builds, workstations, and servers where processors run at high loads for extended periods. The improved conductivity helps keep components within safe operating temperatures under sustained stress.

Liquid Compound / Low-Viscosity Options

Liquid thermal compounds have a thinner consistency than standard pastes, making them easier to spread across larger or irregularly shaped surfaces. They are commonly used in enthusiast builds and professional cooling setups where precise, uniform coverage is important. Due to their low viscosity, care should be taken during application to prevent spillage onto surrounding components.

Putty / Specialised Thermal Compounds

Thermal putty and specialised compounds are designed for applications where a more rigid or pre-formed material is required. Phase-change compounds, for example, soften under heat to improve surface contact over time. These options are well-suited to industrial electronics, power components, and scenarios where re-application is infrequent or difficult. Some formulations also offer electrical insulation properties.

Dispensing Formats

Thermal grease is available in several dispensing formats to suit different application needs. Syringe formats offer precise control for small surface areas, while larger tubes or cartridges are suited to higher-volume or industrial use. Pre-applied pads and sheets provide a convenient, mess-free alternative for consistent coverage. The right format depends on the volume required and the level of precision needed during installation.

Key Benefits of Thermal Grease

The application of thermal grease offers several benefits in computer systems and other electronic devices:

• Improved thermal conductivity: The primary benefit of thermal paste is the enhancement of thermal conductivity between a heat-generating component and a heat sink. By filling in gaps and imperfections, thermal paste creates a more effective transfer of heat from the component to the heat sink.
• Reduced temperature: Efficient thermal conductivity leads to lower temperatures for the heat-generating component. When the heat is effectively dissipated through the heat sink, the component can maintain optimal operating temperatures.
• Prevention of air pockets: Air pockets or gaps between the component and the heat sink hinder the transfer of heat. Thermal paste eliminates these air pockets by filling in the microscopic imperfections and creating a continuous thermal pathway.
• Even distribution of pressure: Thermal paste acts as a cushioning material between the component and the heat sink. It helps to ensure even distribution of pressure across the mating surfaces, avoiding uneven contact and potential damage.
• Easy installation and removal: Thermal paste is relatively easy to apply and remove. It usually comes in a syringe or small container, and a thin layer can be evenly spread on the component using a thermal paste applicator or other suitable tools.

How to Choose the Right Thermal Grease

Consider the following factors before making your choice:

• Application type: Different applications have different thermal demands. A standard desktop CPU build has different requirements from a high-performance server or industrial power component, so match the product to the intended use.
• Thermal conductivity: Measured in W/mK, this indicates how efficiently the compound transfers heat. Higher values suit demanding applications, while standard conductivity levels are sufficient for most everyday builds.
• Operating temperature range: Ensure the thermal grease is rated for the temperature extremes of your application. Some compounds are suited to wide operating ranges, including very high or very low temperatures, which matters for industrial or outdoor environments.
• Physical state: Thermal greases range from thin liquids to thick pastes and solid putties. The consistency affects how the compound is applied and how well it conforms to the surface. Choose a physical state that suits your mounting method and surface geometry.
• Dispensing method: Consider how the product is packaged and how it will be applied. Syringe formats offer precision, while pre-applied sheets suit high-volume or automated assembly. Choose a dispensing method that aligns with your workflow.
• Component sensitivity: Some thermal compounds are electrically conductive and can cause short circuits if they spread beyond the intended area. For sensitive components, opt for a non-conductive formulation to reduce the risk of damage during application.
• Standards and approvals: For regulated industries or safety-critical applications, check whether the thermal grease holds relevant certifications. Some formulations meet specific standards for use in medical, aerospace, or industrial environments.
• The optimal amount needed: Applying too much or too little thermal grease can both reduce performance. A thin, even layer is typically sufficient to fill surface imperfections without spreading beyond the component boundary.

Applications of Thermal Grease

Thermal grease is used across a wide range of industries and applications wherever efficient heat transfer between components is critical. Some of the most common uses include:

• Computer CPUs: This is one of the most widespread uses of thermal grease. It is applied between the processor and its heat sink to ensure efficient heat dissipation and prevent overheating during operation.
• Graphics Processing Units (GPUs): Thermal paste is essential for both consumer and professional graphics cards. Maintaining stable temperatures across the GPU die helps sustain performance during intensive rendering or gaming workloads.
• Chipsets: Chipsets on motherboards generate heat during operation and benefit from thermal grease to improve contact with their cooling solutions, helping maintain stable system performance.
• Power transistors: Power transistors in both consumer and industrial electronics require effective thermal management. Thermal conductive paste is commonly applied between transistors and heat sinks to handle the significant heat generated under load.
• LED lighting: LEDs, including industrial lighting applications, generate heat at the base of the component. Thermal grease helps transfer that heat away from the LED junction, supporting consistent light output and extending component lifespan.
• Overclocking and custom cooling solutions: Enthusiasts who push hardware beyond standard operating limits rely heavily on high-quality thermal grease. In custom cooling setups with liquid cooling blocks or large tower coolers, effective heat transfer paste is critical to maintaining safe temperatures under sustained high loads.

Your Trusted Supplier & Distributor of Thermal Paste & Thermal Grease in New Zealand

RS New Zealand is a trusted supplier and distributor of high-quality thermal paste and thermal grease. We offer an extensive range of heat transfer pastes, from reputable brands such as Fischer Elektronik, Electrolube, and RS PRO, ensuring you have access to reliable, high-performance products for any application.

Beyond thermal grease and thermal paste, we also offer a range of thermal management components, such as thermal pads and thermostats, to support a complete cooling solution.

Explore our user-friendly online site for the full range of products and have them shipped directly to your site or home at your convenience. With our flexible delivery options, you can receive your products precisely when needed. For comprehensive details on delivery times and fees across New Zealand, please consult ourDelivery page.