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Thermal Paste vs Thermal Pads: What‘s the Difference?

Keeping computer components cool is critical to performance and longevity. Two of the most common ways to facilitate heat transfer away from hot components like CPUs and GPUs are thermal paste and thermal pads. But what are the key differences, and which solution works better? Let‘s take a comparative look.

What Are Thermal Paste and Pads?

First, a quick explanation of what exactly these products are.

Thermal paste is a thermally conductive compound, usually silicone or ceramic based, that is applied as a layer between a hot computer component and a heat sink. The paste fills microscopic gaps in the surfaces, allowing efficient transfer of heat away from the component. Common brand names include Arctic Silver, Noctua NT-H1 and Thermal Grizzly Kryonaut.

Thermal pads, meanwhile, are solid pieces of thermally conductive material used for the same purpose. They are positioned as an interface between the component and heat sink to pull heat away. Thermal pads are typically made of materials like silicone, acrylic, graphite or fiberglass. Popular options include Fujipoly Extreme Thermal Pads and Innovation Cooling Graphite Thermal Pads.

So in short, both products aim to lower component temperatures by effectively moving heat from the source (e.g. CPU die) to the heat sink where it can dissipate. Now let‘s look at some key differences.

Thermal Conductivity

An important performance metric is thermal conductivity. This measures how effectively heat transfers through a material, rated in W/mK.

In general, thermal pastes offer higher thermal conductivity compared to pads, usually around 7-9 W/mK. They are specifically engineered for maximum heat transfer capabilities.

Thermal pads have lower conductivity depending on material, from 1 W/mK on the low end to 20+ W/mK for high-end graphite pads. Even the best pads usually fall short of top thermal pastes.

However, conductivity alone doesn‘t tell the whole story. Real-world effectiveness depends on other factors like surface contact, thickness, installation quality and more.

Surface Contact and Gaps

Here’s an area where thermal paste has a strong advantage. Since it‘s a conformal substance, paste can fill microscopic pits and valleys on mating surfaces very effectively. This optimizes contact area for heat transfer.

Pads, on the other hand, are solid sheets that don’t deform as easily. There can still be significant air gaps between a pad and uneven surface, impeding conductivity. Some pad materials like silicone are more malleable than others, however.

So for components like CPUs with delicate die surfaces, thermal paste generally makes better contact for superior cooling. Pads work best when joined surfaces are extremely flat and smooth.

Thickness Differences

Another consideration is application thickness. Thermal paste layers are very thin,less than 0.1mm in most cases. This allows for higher efficiency heat transfer thanks to the small cross section.

Thermal pads need to be considerably thicker to provide a usable solid interface, from 0.2mm up to 1-2mm. This added thickness causes more thermal resistance.

So again paste holds the edge for unimpeded heat conduction pathway thanks to its ultra thin application.

Ease of Installation

Installation procedure is similar for both solutions – clean mating surfaces thoroughly, apply product, mount heat sink. But thermal paste can be a bit trickier to work with.

Since it‘s a viscous fluid, paste requires careful application to avoid making a mess or using too much/too little for proper coverage. There are some best practices to follow. It spreads easier with tools like a plastic spreader or old credit card.

Thermal pads have an advantage in simplicity. Cut a pad to size if needed, peel the liner, stick in place and go. Less precision required. Just be sure pad fully contacts all surfaces. If reusing pads, additional adhesive may be needed.

So pads get the ease of use vote, especially for less experienced DIY builders. Thermal paste just needs some practice.

Conductivity Concerns

One caution about metal-based thermal pastes and graphite pads – they are electrically conductive. If the product migrates off of matings surfaces onto other PCB components, it could cause a dangerous short circuit when power is applied.

For this reason, dielectric/non-conductive materials like silicone paste or silicone/acrylic pads are generally the best choice for overall safety. They carry no risk of shorts.

Longevity Differences

Both thermal paste and pads will degrade slowly over time, experiencing drying and chemical breakdown effects. This lowers cooling performance, meaning periodic replacement is required.

Thermal paste generally has a shorter viable service life, often 1-3 years depending on usage levels before reapplication is recommended. There are some top shelf pastes that claim 5+ year lifespans like Noctua NT-H1.

Thermal pads can endure significantly longer, up to 5-10 years thanks to slow wearing solid construction. So while pads may lack in initial conductivity, they maintain effectiveness over a longer term before replacement is needed.

Thermal Paste Pros

  • Higher possible thermal conductivity
  • Thinner application for minimal resistance
  • Conforms tightly to uneven surfaces
  • Large variety of materials and brands
  • Various application tools available

Thermal Pads Pros

  • Simpler installation
  • Some materials offer high conductivity
  • No mess like paste application
  • Maintain function longer term
  • Can reuse if gentle removal

Which is Better for PC Cooling?

For most PC enthusiasts, hardcore overclockers and gamers where maximum cooling is vital, high-performance thermal paste remains the top choice. Materials like diamond or metal particle pastes guarantee excellent thermal interface for hot gaming rig processors and graphics chips. Easy access within the DIY space makes experimenting with different pastes simple too.

Of course paste requires meticulous application and more frequent replacement to keep CPUs degrees cooler during intense workloads. But benefits outweigh for most demanding users.

For more modest PC builds or office work systems, quality thermal pads offer a simpler solution that still effectively transfers heat away from delicate chips. Silicon-based pads from makers like Fujipoly provide reliable, long-lasting cooling without hassle. Acrylic and specialty graphite pads work well also. Just ensure full contact coverage during mounting.

Either solution will lower core temperatures considerably compared to no interface material. And aftermarket options are cheap insurance to enhance airflow cooling performance and protect fragile computer microchips. Whether you pick paste or pads, proper heat mitigation makes computing systems more stable, boosts speed potential and extends overall lifespan!