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Thermal Paste vs. Thermal Pad: What’s the Difference?

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Thermal Paste vs. Thermal Pad: What’s the Difference?

Key Points

  • Thermal paste and thermal pads are used to transfer heat away from computer components, but they differ in terms of materials and heat conductivity.
  • Thermal paste options include metal-based, liquid metal-based, diamond carbon-based, carbon-based, ceramic-based, and silicone-based.
  • Thermal pads are typically made of silicone, acrylic, or graphite, and they are thicker than thermal paste.
  • Thermal paste is generally more effective than thermal pads in terms of heat transference and filling micro-gaps on surfaces.
  • Thermal pads are more suitable for short-term use or benchmarking, while thermal paste is recommended for long-term use in high-heat components like CPUs and GPUs.

Overheating is one of the primary causes of computer issues, and it can damage the components beyond repair in the blink of an eye. CPUs and GPUs are among the most heat-sensitive parts of your computer.

Unfortunately, they’re also the ones that generate much of the heat in your computer. To alleviate much of the heat generation, we use cooling systems. Traditionally, we use thermal paste and a fan attached to heat pipes to move the heat away from the CPU, but thermal pads are becoming more popular.

So, which is better in the battle of thermal pads vs. thermal paste? Let’s examine these two cooling options.

Thermal Paste vs. Thermal Pad: Side-by-Side Comparison

Thermal PasteThermal Pad
FunctionHeat TransferHeat Transfer
Necessary Adhesive?NoSometimes
MeasurementVolumeThickness
Alternative NamesThermal Grease, Thermal Gel, Thermal Goop, Thermal Compound, Thermal Interface Material, CPU GreaseThermal Relief Pad
Thermal Conductivity at 20°C7.5 W/mKVaries, 1–20 W/mK
Material TypesMetal, Liquid Metal, Diamond Carbon, Carbon, Silicone Silicone, Graphite, Acrylic

Thermal Paste vs. Thermal Pad: What’s the Difference?

Thermal paste and pads perform the same function: heat transfer from the component to the fan to the air. However, the method by which they achieve this goal differs. Thermal paste and thermal pads have several differences, including their average thermal conductivity, the materials used to produce them, and how we measure them. Let’s look at those differences.

Material Type

There are many different types of thermal paste and a few types of thermal pads. Thermal paste can be made of metal, liquid metal, carbon, diamond carbon, or silicone. Pads are typically made of silicone, graphite, or acrylic.

Thermal Paste: Metal-Based

Metal-based thermal pastes typically contain silver or aluminum, as these materials are especially heat-conductive. However, they are also electrically conductive. So, you must take special precautions when using a metal-based thermal paste.

If a metal-based thermal paste containing silver or aluminum touches one of the circuits on the printed circuit board (PCB), it will cause a short circuit when the computer turns on and sends power to the PCB. A short circuit in the PCB could permanently damage it and even render the entire board useless. For this reason, metal-based thermal pastes are not recommended for first-time users.

To avoid spillage, install electrical tape around the components on which you apply thermal paste. Electrical tape will prevent any spillage from touching components protected by the electrical tape without impeding their function.

Thermal Paste: Liquid Metal-Based

thermal paste vs. thermal pad
Thermal paste acts as an interface between a heat-producing electrical component and a heat sink, facilitating heat transference between the two components.

Liquid metal-based thermal paste is not a paste; it’s a liquid. It typically contains gallium, which makes it highly unwieldy for new users. Thus, we recommend not using liquid metal-based thermal paste unless you’re an expert.

Gallium is great for heat conduction and it contains electrically conductive metals. Like with silver or aluminum thermal paste, it will conduct on the PCB. If the gallium in the paste conducts on the PCB, it could fry the PCB and render it useless. It’s also much harder to prevent liquid metal-based pastes from spilling as they’re not as thick as a paste because they’re liquid. 

Additionally, gallium reacts with aluminum, a common metal found in the construction of heat sinks for CPUs. So, the paste may damage the CPU directly through this reactivity.

Thermal Paste: Diamond Carbon-Based

Thermal paste can also be made using diamond carbon to transfer heat. Diamonds are five times more effective at transferring heat than silver, making diamond carbon a highly effective mode of heat transfer for computer components.

However, the diamond industry regulates the sale and prices of diamond powder, making these pastes more expensive. While diamond carbon-based thermal pastes may be among the most effective, they’re also among the most expensive options.

Still, people with healthy budgets may want to spring for a diamond carbon-based thermal paste as these can more effectively cool your components without scratching the metal surfaces.

Thermal Paste: Carbon-Based

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Carbon-based thermal pastes contain tiny carbon fibers that transfer heat from the CPU to the heat sink. However, carbon fibers aren’t exceptionally good at transferring heat, making them a less effective option than metal- or diamond-based thermal pastes.

The most appealing part of a carbon-based thermal paste is that it isn’t electrically conductive. So, it’s an excellent choice for any beginner who might accidentally spill the thermal paste or apply too much.

Despite this, if you have some experience applying thermal paste, a more heat-conductive material will serve you better.

Thermal Paste: Ceramic-Based

Ceramic-based thermal pastes are the most popular on the market by far. They’re not electrically conductive, making them excellent for beginners. However, ceramic is similar to carbon because it isn’t particularly heat-conductive, meaning it won’t transfer heat as effectively as metal or diamond carbon. Still, it’s extremely affordable and easy to find.

Thermal Paste: Silicone-Based

Silicone-based thermal pastes are excellent all-rounder options for beginners and experts alike. They feature superior heat-conductivity to carbon and ceramic and can spread evenly without spilling. Additionally, these thermal pastes are electrically insulative. So they won’t cause any short circuits, even if you spill a bit on your PCB.

Silicone thermal paste is a perfect choice for someone looking for superior performance. However, they are comparatively more expensive than other types of thermal paste. Its prices are similar to those of diamond carbon thermal paste. So, your budget will have to be appropriately high to accommodate it.

Thermal Pads: Silicone

thermal paste vs. thermal pad
Thermal pads are a solid thermal interface material that is positioned between components and heat sinks.

Silicone is one of the most popular materials for thermal pads. It offers a similar heat conductivity to silicone thermal paste. Additionally, you can manufacture silicone pads in a wide range of thicknesses and compression levels. It’s also electrically insulative. So, it’s a highly versatile substance for electronics.

Thermal Pads: Acrylic

Acrylic is another option for thermal pads. The material cost of an acrylic thermal pad is lower than that of a silicone pad, making it a more cost-efficient choice. However, its thermal conductivity is lower, and it doesn’t conform to surfaces, as well as silicone. So, it’s a less effective choice in the long term.

Thermal Pads: Graphite

Graphite pads are excellent for systems that require a very thin but highly conductive thermal interface material. However, they are also highly electrically conductive.

So, ensure that your graphite pad is securely placed between the heat sink and the CPU with no hanging edges. If the graphite pad touches the PCB while the computer has power running to it, it could fry the motherboard.

Heat Conductivity

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The heat conductivity of a thermal interface material is dependent on the type of material used. However, generally, we consider the heat conductivity of thermal paste to be around 7.5 W/mK. This conductivity is lower than that of some thermal pads, which boast a rating of 15–20 W/mK.

However, it is also important to remember that thermal pads are generally thicker than thermal paste, which lowers their effective heat conductivity. The thicker the thermal pad, the lower its effective heat conductivity.

Thermal pads for high-heat components have their thickness measured in microns. Any thicker and their heat conductivity would be too low to use for high-heat components.

Necessary Tools

Most thermal pads require you to purchase a separate adhesive. Unlike thermal paste, which stays in place on its own, thermal pads will slip and move if not adhered to the surface of the component.

Some thermal pastes, namely those made of silver, aluminum, or liquid gallium, require you to use electrical tape to protect the surrounding circuits from the conductive metal in the paste. Without the electrical tape, you run the risk of short circuits frying the motherboard and rendering it useless.

Thermal Paste vs. Thermal Pad: 5 Must-Know Facts

  1. Thermal paste and pads provide additional heat transference from components to the heat sink.
  2. Thermal paste provides better heat transference than thermal pads because it is a paste that can conform to micro-gaps on a surface.
  3. Thermal pads conform to the shape of the heat sink and typically need to be replaced if the heat sink is removed.
  4. Both thermal pads and thermal paste degrade over time and must be replaced.
  5. Depending on workload, thermal paste must be reapplied every few months or years.

Thermal Paste vs. Thermal Pad: Which One Is Better?

thermal paste vs. thermal pad
Thermal paste is generally considered to be more efficient and effective than thermal pads, but there are times when thermal pads may be considered more beneficial.

In almost all situations regarding consumer PCs, thermal paste outperforms thermal pads. Since thermal paste is a paste — meaning a substance that behaves like a solid until sufficient stress is applied — it conforms better to surfaces. It can easily fill micro-gaps on a surface, significantly improving heat transference.

Additionally, there are more options when it comes to thermal paste materials than thermal pad ones. Substances such as diamond powder offer more options in terms of heat conductivity.

You will need to replace the thermal pad when you remove the heat sink. Since the thermal pad will conform to its shape, you’ll need a new one when you replace the heat sink, or the old one won’t fill the gaps in the heat sink correctly.

Thermal pads also do not fill micro-gaps as effectively as thermal paste. Since thermal pads are solid, they can’t conform to the small space micro-gaps create, making them less effective at heat transference.

Finally, thermal pads must be very thin to transfer heat in high-heat components adequately. Manufacturers typically only recommend using thermal pads for components that are not the main source of heat in a system, like RAM chips.

Thermal pads are too inefficient for high-heat components like CPUs and GPUs. We usually measure the thickness of thermal pads intended for high-heat components in microns. These thermal pads are extremely thin in order to transfer heat efficiently between the component and the heat sink.

When Thermal Pads Are Better

thermal paste vs. thermal pad
Thermal pads may be more useful for people who are testing multiple products that require thermal interface materials.

However, there is one time that thermal pads are more effective than thermal paste. If you aren’t planning on using a CPU or GPU long-term and are only trying to benchmark it, you are probably better off using a thermal pad. This condition is especially true if you plan to benchmark several processors.

Since the heat sink won’t be on the processor for very long during benchmarking, the pad won’t have time to conform to the heat sink fully. Thus, you can reuse it if it has no pre-packaged adhesive.

Additionally, since you’ll use the same thermal pad several times, you’ll more effectively replicate the environment for each successive processor test. However, to reuse your thermal pad, you’ll need to purchase a separate adhesive like thermal tape or thermal glue to keep it in place.

When choosing a thermal pad or paste, you must consider the materials used to make the thermal interface material. Silicone is a good all-rounder available as both a paste and a pad.

However, you must be careful if you use silicone paste and intend to switch to a silicone pad. Silicone solvents degrade silicone solids. So, ensure you’ve correctly cleaned your CPU of any remaining thermal paste, or the silicone paste could degrade the pad.

Considerations for Thermal Paste Users

Additionally, if you’re using thermal paste on a high-workload system, you’ll need to replace the thermal paste frequently. So, choosing an expensive thermal paste material like diamond powder could be cost-prohibitive if you decide to stick with that material.

However, choosing a less expensive material like ceramic or carbon will lower the heat transference of your thermal paste. So, it’s a delicate balancing act.

You’ll also want to consider whether the material you’ve chosen for your thermal interface material is electrically conductive, as this will require you to take special precautions when using it. Graphite, silver, gallium, and aluminum are electrically conductive materials, while silicone is electrically insulative. Diamond, carbon, and ceramic are non-conductive. 

If you choose an electrically conductive material, you’ll want to ensure you have some electrical tape to install around your CPU to guarantee that the conductive material doesn’t touch any of your circuits. An electrically conductive material will destroy a PCB if power is sent to the circuits.

Thermal Paste vs Thermal pads infographic

Frequently Asked Questions

What is thermal paste?

Thermal paste is a thermal interface material that transfers heat between electrical components and a heat sink.

What is a thermal pad?

Thermal pads are a solid thermal interface material adhered between an electrical component and a heat sink to transfer heat between the component and the heat sink.

What is the heat conductivity of thermal paste?

On average, thermal paste has a heat conductivity of 7.5 W/mK. However, this can be higher if the paste is made with more conductive materials.

What is the heat conductivity of a thermal pad?

The heat conductivity of a thermal pad differs based on the materials used to make them. Thermal pads have a rough conductivity range of 1–20 W/mK.

What is better, thermal paste or thermal pads?

Thermal paste is generally considered better than thermal pads because it conforms better to micro-gaps in the heat sink’s surface, improving conductivity.

What is thermal paste made of?

Thermal paste can be made of many materials. It is typically made of metal, silicone, carbon, ceramic, or diamond carbon.

What are thermal pads made of?

Thermal pads are typically made of silicone, acrylic, or graphite, but some manufacturers use polyester, aluminum, or fiberglass.

Do thermal pads require adhesive?

Thermal pads must be bound to the component to stay in place. Use thermal glue or tape to attach the thermal pad to the component.

Do thermal pads leave behind residue?

Thermal pads may leave residue behind when removed from a component. This residue can be removed with isopropyl alcohol or acetone.

How do I clean thermal paste off my CPU?

You’ll need to clean the old thermal paste off your CPU when you replace it. You can achieve this using isopropyl alcohol and cotton swabs. Be gentle and diligent; removing all of the old thermal paste from the CPU will take time.

How often should I replace my thermal paste?

Replacing thermal paste can be necessary every few months to every few years. It depends on your CPU’s workload. The more you use your CPU, the faster the thermal paste degrades.

Do thermal pads need to be replaced?

Thermal pads degrade over time! They typically don’t have to be replaced as often as thermal paste, but most thermal pads will last five or six years before they need to be replaced.

Do thermal pads go bad?

Thermal pads have a shelf life of about eight years. After eight years, the materials in the thermal pad will have degraded past the usability point.

Is thermal paste sticky?

Thermal paste is not sticky. It is typically a thick liquid that can be somewhat oily on first application. 

Does thermal paste go bad?

Thermal paste doesn’t really “go bad,” but the liquid part of the paste can evaporate over time, making it harder to apply.

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