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

Introduction: Thermal Pads vs. Thermal Paste

Electronic equipment needs thermal control to avoid overheating, which damages components and performance. CPUs, GPUs, and MOSFETs must transmit heat for stability and operation. Two solutions for heat dissipation are thermal paste and thermal pads, which are thermal interface materials. Thermal paste, a semi-liquid material, fills tiny air gaps between components and heat sinks for heat transmission. Solid, mat-like thermal pads span large or uneven gaps. 

Thermal paste has thermally conductive particles in a liquid base. Meanwhile, thermal pads use silicone and ceramics for flexibility and insulation. Ultimately, the argument over thermal paste vs. thermal pad centers on application, convenience of usage, and performance.

The Composition: Thermal Pads vs. Paste

Thermal Pads

Thermal pads are thermally conductive yet electrically insulating. They combine silicone or polyurethane with ceramics, graphite, or metallic oxides. For instance, high-end thermal pads can have a thermal conductivity of up to 12 W/mK in the latest designs. They have thicknesses from 0.2mm to 20mm for gap-filling. Because they are solid sheets, they cannot fully conform to microscopic imperfections. It limits their performance on uneven surfaces compared to paste. However, their composition renders them easy to handle, cut, and apply. Pads also provide electrical insulation above 13,000V for some models. They are safer for power MOSFETs and memory chips since simplicity and insulation matter more than absolute conductivity.

Thermal Paste

Thermal paste has a liquid or semi-solid base (silicone, synthetic oils, or organic compounds) with conductive aluminum, zinc oxide, silver, or carbon nanomaterials. Its thermal conductivity can range from 4 to 6 W/mK for standard pastes and up to 13 W/mK for high-performance ones. Unlike pads, paste spreads thinly and fills microscopic gaps between surfaces. It provides a lower thermal resistance for high-power CPUs and GPUs. Nevertheless, adding metallic particles can make some thermal pastes slightly conductive for short circuits if misapplied. Their liquid nature allows precise application, but it also demands handling. Thermal paste requires skill to avoid mess and accomplish an even, thin layer that augments contact and heat transfer.

So, thermal paste vs. thermal pad composition affects heat conductivity, usefulness, and safety.

Thermal Conductivity: Thermal Pads vs. Paste

Thermal Pads

Thermal pads have higher thermal conductivity ratings, up to 12 W/mK for high-quality options. But they are less effective in practice due to their higher thermal resistance. Like memory chips, VRMs, or motherboard power supplies, pads suit uneven surfaces or large gaps. E.g., a 1mm thick thermal pad can insulate up to 13,000V for safe, broad applications. Yet, their inability to fill microscopic gaps limits heat transfer in CPUs or GPUs. When convenience matters more than heat dissipation, thermal pads better fit low-power electronics or delicate PCBs.

Thermal Paste

Thermal paste may have lower thermal conductivity ratings (4-6 W/mK) but works better due to its low thermal resistance. It fills the tiniest air gaps between the heat sink and component for CPUs and GPUs under heavy load. For instance, a paste can keep CPU temperatures at 89.4°C. Pads may allow temperatures to rise above 97.2°C during stress tests. Though applications can be messy, paste is used in high-performance gaming PCs and workstations. For thermal paste vs. thermal pad, paste tops precision-critical tasks demanding maximum heat transfer efficiency.

Application and Ease of Use

Thermal Pads

Thermal pads are very easy to use. You peel off the backing and place it on the component's surface, like a CPU, GPU, or motherboard MOSFET. No special tools or skills are necessary. They are handy for large gaps or uneven surfaces, as they come in multiple thicknesses. Pads don't leave any mess and are reusable after initial application for beginners or quick assembly tasks. Nonetheless, for maximum effectiveness, verify that the pad fully covers the surface. If your goal is simplicity, thermal pads are better in thermal paste vs. thermal pad applications.

Thermal Paste

The thermal paste needs more precision and skill to apply. You need to spread it evenly over the component's surface using a small amount. Too much or too little affects performance. Beginners may find it messy since the paste can overflow and stain nearby parts. For instance, improper handling can cause short circuits if electrically conductive paste contacts other components. Yet, its paste-like structure fills microscopic gaps for better heat transfer. Thermal paste also works better with uneven surfaces when even a thin layer can lower temperatures (up to 8°C than thermal pads). For experienced users, thermal paste offers performance despite its messiness.

Longevity and Durability

Thermal Pads

Thermal pads degrade faster under repeated thermal cycling. Over time, the material can become brittle due to expansion and contraction. High-end thermal pads may last many years under moderate conditions. Yet, their performance drops in high-temperature environments. Also, pads with larger thicknesses are more prone to wear in power-dense GPUs or power supply units. Once degraded, they lose their gap-filling properties, which increases thermal resistance. It can prompt overheating and impact the device's reliability over time. Replacing thermal pads can also be tricky. They may stick to components and leave a residue that hinders heat transfer.

Thermal Paste

Thermal paste has better durability under repeated thermal cycling. It remains practical because it hardens slightly over time for contact between the heat sink and the component. High-quality thermal pastes with metal or ceramic particles last 3-8 years under normal conditions. Cheaper pastes with low conductivity may dry out sooner in systems with high heat output. Even with this drying, paste offers greater heat transfer than degraded pads. However, the paste cannot be reused after disassembly and may need cleaning before reapplication, which adds upkeep effort. In the long term, thermal paste provides better thermal conductivity for critical CPUs and GPUs.

So, when comparing thermal paste vs. thermal pad, paste lasts longer and performs better under thermal stress than thermal pads, which are simpler to handle but deteriorate quicker.

Thermal Pad vs. Thermal Paste: Which is Better for Your Needs?

Conclusion

T-Global offers multiple thermal pads and pastes to solve thermal management problems. Our thermal pads, such as the TG-A1250 with 12.5 W/mK thermal conductivity, bridge gaps between high-power components and heat sinks for heat transfer in autonomous vehicles and industrial control systems. In contrast, our thermal pastes, including the TG-AS808 / TG-S808 with 8 W/mK thermal conductivity, cover tiny surface defects to improve heat dispersion for CPU and GPU cooling when the interface thickness is minimal. Optimizing thermal performance in your application calls for knowing thermal paste vs. thermal pad choices. Browse our thermal management solutions and contact us for experienced advice on your specific requirements. 

See our thermal pads and pastes for different thermal management applications.