How to Apply Thermal Paste? Carbon Thermal Paste Application Methods – Full Surface, Pea-Sized Amount, or Cross Method?

Efficient CPU cooling starts with one crucial component — the thermal interface material (TIM), commonly known as thermal paste. It ensures optimal heat transfer between the CPU and the heatsink. In this guide, we’ll explain how to apply thermal paste step by step, show you the best thermal paste application methods, how much to use, and how each approach — pea-sized amount, grain of rice method, line method, cross method, and spread method — affects cooling performance.

Why Replace Thermal Paste Regularly?

Thermal paste longevity depends on usage and environmental conditions. Over time, the paste dries out and becomes less effective. Aged thermal interface material (TIM) can trap air pockets and reduce conductivity, leading to overheating and system instability.

Regular thermal paste replacement frequency (every 2–3 years) helps maintain stable CPU temperatures. Fresh paste fills microscopic gaps and can reduce CPU temps by 10–15°C. Even the best cooler won’t work efficiently if old paste remains.

The cost of thermal paste and its replacement is minimal compared to the benefit of extending hardware life and improving thermal performance.

Thermal Paste Cleaning and Replacement

Proper thermal paste cleaning is critical before every new application. Remove the old thermal interface material (TIM) using isopropyl alcohol or IPA Wipes, then wait until the surface is dry. For desktops, replace paste every 2–3 years; for high-performance or overclocked systems, once a year is ideal. Always ensure even cooler pressure and recheck CPU temps after reassembly.

Monitoring tools like HWMonitor or HWiNFO help verify that your thermal paste application method was effective. Temperatures above 90°C may indicate improper application or cooler misalignment.

How to apply thermal paste? –  Laptops and GPUs

In laptops, thermal paste replacement frequency can be lower due to compact designs and heat accumulation. Replacing paste in a GPU or CPU can lower temps by 10–15°C. Using thermal paste for GPU specifically designed for high-load devices ensures stable frame rates and improved component longevity. Remember that thermal paste cleaning before application is even more critical in laptops and GPUs due to limited airflow.

Thermal Paste Application Methods – Step by Step

Understanding the right thermal paste application methods helps ensure efficient heat transfer.
Here’s how to do it correctly:

Prepare your workspace — unplug power, remove cooler.

Perform proper thermal paste cleaning using IPA or wipes.

Let the surface dry completely.

Apply the paste using one of the following thermal paste application methods:

• • Pea-sized amount – the most common and beginner-friendly approach.
  • Grain of rice method – similar to the pea-sized but smaller, reducing potential overflow.
  • Line method – best for rectangular CPUs or GPUs.
  • Cross method – ensures full coverage with minimal excess.
  • Spread method – thin layer evenly spread using a spatula.

Tighten the cooler evenly in a cross pattern.

Power up and check temperatures.

Each thermal paste application method has advantages, but full surface spread or cross method typically offers the best performance.
A good rule of thumb: less is more — a pea-sized amount or grain of rice method is usually enough for CPUs.

How Much Thermal Paste Should You Use?

One of the most common questions: how much thermal paste is enough?

Too much paste acts as an insulator, while too little reduces coverage. Apply a pea-sized amount — roughly the size of a small drop — to ensure even contact. The grain of rice method or line method can also be effective, depending on CPU shape.

Avoid excessive application — overflow can cause uneven spreading. The spread method gives precise control for enthusiasts, while cross method helps cover large CPU dies effectively.

Thermal Paste Cleaning – Key to Good Contact

Before applying new paste, always perform a full thermal paste cleaning:

• Use lint-free cloths and isopropyl alcohol.

• Avoid metal tools or direct contact with your fingers.

• Ensure the CPU surface is completely clean and smooth.

Proper thermal paste cleaning ensures maximum adhesion and performance from your thermal interface material (TIM).

Testing Thermal Paste Application Methods

We tested different thermal paste application methods using Carbon Thermal Paste on an Intel i7-14700K (200 W) CPU.

Test procedure:

• Stage 1: 30 min Prime95 – thermal stabilization

• Stage 2: 10 min idle – cooling phase

• Stage 3: 20 min Prime95 – sustained load

The spread method achieved the lowest temperatures, confirming that even coverage ensures optimal heat transfer. Both the pea-sized amount and grain of rice method can be problematic — it’s easy to apply too much or too little paste, which may lead to uneven coverage, trapped air pockets, and reduced cooling efficiency.

Surface Quality and Heat Transfer

The smoother the CPU surface, the more effective the thermal interface material (TIM) becomes. AMD and Intel CPUs vary in size and design, so the ideal thermal paste application method depends on CPU shape. Always ensure full contact without air pockets or excess material.

Types of Thermal Paste and Alternatives

There are several types of thermal paste and thermal paste alternatives:

• Ceramic paste – non-conductive, safe for beginners.

• Silicone paste – affordable but lower thermal performance.

• Metal-based paste (Silver, Gold) – excellent conductivity for enthusiasts.

• Carbon Thermal Paste – combines conductivity and durability.

• Thermal pads or liquid metal – common thermal paste alternatives for specific use cases.

When selecting paste, check its thermal conductivity (W/mK) and thermal paste longevity — good pastes last for years without drying.

Buying the Right Thermal Paste for CPU and GPU

When shopping for thermal paste for GPU or CPU, look at:

• Thermal conductivity (W/mK) – the higher, the better.

• Ease of application – especially important for beginners.

• Longevity and viscosity – affects how often you need to reapply.

Carbon Thermal Paste 15.2 W/mK from AG TermoPasty provides premium performance, easy application, and long-term durability. It’s non-conductive, odor-free, and ideal for both CPUs and GPUs.

Thermal Paste Replacement Frequency and Maintenance

The average thermal paste replacement frequency is every 2–3 years, or annually for overclocked systems. Regular maintenance ensures consistent performance and prevents thermal throttling. Monitor your thermal paste longevity and reapply when CPU temps start rising under load.

Summary – How to Apply Thermal Paste Correctly

To summarize the best thermal paste application methods:

• Clean the surface thoroughly (thermal paste cleaning).

• Apply a pea-sized amount or use the cross method.

• Avoid overapplication — the goal is full, thin coverage.

• Check temperatures after reinstallation.

Properly applied thermal paste ensures efficient cooling, stability, and hardware protection.

Carbon Thermal Paste Test – Final Conclusions

The Carbon Thermal Paste test confirmed that full spread and cross methods provide the best results. Regular maintenance and correct thermal paste replacement frequency keep your CPU and GPU performing efficiently.  Remember — a small pea-sized amount of paste can make a huge difference in performance and lifespan.

Below you’ll find a video of the tests, and you can read more about Thermal Conductivity at this link.