Thermal paste, also called thermal compound or thermal interface material, is a heat-conductive substance applied between a chip and its cooler to eliminate microscopic air gaps that would otherwise block heat transfer. Metal surfaces look smooth to the eye but are uneven at a microscopic level, and air is a poor conductor of heat. Paste fills those gaps with a material that conducts heat far better than air, letting the heat sink or cold plate actually do its job.
What changed in 2026
- Pre-applied paste on stock coolers got more consistent, reducing the number of builds that ran hot purely because of a bad factory application.
- Carbon-based and graphite pastes gained ground as a middle option between standard silicone-based paste and liquid metal, offering better conductivity without the electrical risk.
- More case and cooler manufacturers started recommending repaste intervals directly in product documentation, as awareness grew that paste degrades over years, not indefinitely.
Why paste matters more than people expect
A heat sink or cold plate can only cool what it is actually touching. If a layer of trapped air sits between the chip's surface and the cooler, that air acts as an insulator rather than a conductor, and temperatures rise even with an otherwise excellent cooling setup. This is why a premium cooler with a bad paste job can underperform a budget cooler applied correctly — paste application often matters more than the cooler itself within a reasonable price range.
Types of thermal paste compared
| Type |
Conductivity |
Electrical risk |
Best for |
| Silicone-based |
Good |
None |
Most builds, easy application |
| Carbon/graphite-based |
Very good |
None |
Slight upgrade over silicone |
| Metal-based (non-liquid) |
Very good |
Low |
Enthusiast builds |
| Liquid metal |
Excellent |
High |
Experienced builders only |
How to apply thermal paste
- Clean the old paste off first with isopropyl alcohol and a lint-free cloth, on both the chip surface and the cooler base.
- Use a small dot or thin line in the center of the chip rather than spreading it manually — the pressure of mounting the cooler spreads it evenly on its own.
- Do not overdo the amount. A pea-sized dot for most consumer CPUs is enough; more paste risks squeezing out to the edges rather than improving conductivity.
- Mount the cooler with even pressure, tightening screws in a diagonal or crisscross pattern rather than one side at a time.
When to reapply thermal paste
Most silicone-based pastes hold up for three to five years before they dry out and lose effectiveness, showing up as gradually rising idle and load temperatures with no other explanation. If you have not repasted a build in that window and temperatures have crept up, that is the first thing to check before assuming the cooler itself, covered in our heat sink guide, has failed.
FAQ
Does more thermal paste mean better cooling?
No. A thin, even layer conducts heat efficiently; a thick layer can trap paste in the middle and actually reduce conductivity compared to a properly applied thin layer.
Is liquid metal worth the risk?
For most builders, no. The performance gain over a good non-conductive paste is modest, while the risk of shorting a component if it spreads is real and irreversible.
How do I know if I need to reapply paste?
Rising temperatures over time with no hardware or workload changes, especially on a build older than three years, is the classic sign of dried-out paste.
Can I use toothpaste or another substitute in an emergency?
No. Non-thermal substances do not conduct heat effectively and can damage components. Use an actual thermal compound, even a cheap one, rather than an improvised substitute.
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