Yes, thermal grease and thermal paste are the same thing. These two terms, along with “thermal compound” and “thermal interface material,” all refer to the same category of product: a semi-liquid substance applied between a processor and its cooler to improve heat transfer. The different names come from different communities and manufacturers, but they all describe the same function and the same types of products.
Why So Many Names Exist
The variety of names traces back to how the product is described from different angles. “Thermal paste” refers to its consistency. “Thermal grease” refers to its greasy, non-curing texture. “Thermal compound” describes it as a mixture of materials. You’ll also see “heat sink compound” or “CPU paste” in older documentation. All of these land on the same shelf at the store.
Some people assume “grease” implies a lower-quality or older-style product, but that’s not the case. Manufacturer spec sheets frequently use “thermal grease” and “thermal paste” interchangeably, sometimes even within the same product listing.
What Thermal Paste Is Made Of
Most thermal pastes use a silicone or hydrocarbon base mixed with thermally conductive fillers. The fillers are what do the real work of moving heat, and they come in a few varieties that affect both performance and safety.
Ceramic-based pastes use electrically insulating fillers like zinc oxide or aluminum oxide. These are the safest option for most builders because even if some paste squeezes out onto nearby circuits, it won’t cause a short. The tradeoff is slightly lower thermal performance.
Metal-based pastes contain micronized silver or other metal particles suspended in a silicone or ceramic medium. Silver compounds can reach thermal conductivities of 3 to 8 W/mK or higher. The downside: metal-based paste can conduct electricity. If it spills onto circuit traces, it can cause damage or malfunction.
Carbon-based pastes sit in a sweet spot, offering good conductivity (around 8.5 W/mK for high-end options) without the electrical risk of metal particles. A 4-gram tube of carbon-based compound typically costs around $10.
Liquid metal is the extreme end of the spectrum. Made from alloys like galinstan, these products exceed 13 W/mK in thermal conductivity but are difficult to apply evenly, electrically conductive, and corrosive to aluminum heat sinks. They’re not traditional “paste” in the usual sense and are best left to experienced builders.
How Performance Varies
The average tube of thermal paste falls somewhere in the 4 to 8.5 W/mK range. Stock paste that comes pre-applied on coolers tends to sit around 4 W/mK, which is adequate for most systems running at default speeds. Aftermarket pastes with silver or diamond particles push higher, and the best carbon-based compounds land around 8.5 W/mK.
For most people, the difference between a 4 W/mK paste and an 8.5 W/mK paste translates to a few degrees Celsius under load. That matters if you’re overclocking or running a high-powered GPU in a compact case, but for a standard desktop build, even budget paste does the job well.
How to Apply It
Intel recommends placing a pea-sized or rice-grain-sized dot in the center of the processor’s heat spreader. That’s it. Resist the urge to spread it manually. When you press the cooler down, the mounting pressure spreads the paste into a thin, even layer that fills microscopic imperfections in the metal surfaces.
When securing the cooler, tighten the screws in a diagonal pattern, like drawing an X. This distributes pressure evenly and prevents the paste from being pushed to one side. If your cooler came with paste pre-applied to its base plate, you can skip adding your own.
How Long It Lasts
Most thermal pastes remain effective for 3 to 7 years in a desktop PC running at stock settings. Some users report perfectly fine temperatures after a decade on original paste. The compound does dry out over time, gradually losing its ability to fill gaps and transfer heat, but this is a slow process in most cases.
Laptops are harder on thermal paste because of higher sustained temperatures in tighter spaces. Paste in a laptop may start degrading in as little as six months to two years. If you notice your laptop running hotter than it used to, dried-out paste is a common culprit.
Some high-end compounds, like those designed for extreme overclocking, are known to dry out faster, sometimes within a year. Standard silicone-based pastes tend to be more durable over time. If you’re not overclocking and your temperatures look normal, there’s no need to reapply on a fixed schedule.
Thermal Paste vs. Thermal Pads
One product that is genuinely different from thermal paste is a thermal pad. These are solid, pre-cut sheets of thermally conductive material, usually made from silicone rubber with filler additives on a fiberglass substrate, typically around 0.25 mm thick. They’re used where the gap between a chip and a heat sink is too large or uneven for paste to bridge effectively, such as on VRM components or memory chips on a graphics card.
Thermal paste with the same rated conductivity will outperform a pad because the paste layer can be thinner, which means lower thermal resistance. Pads are chosen for convenience and for components where the gap is simply too wide for paste to work. For CPUs and GPUs, paste remains the standard choice.