Best CPU Cooling Paste

Best CPU Cooling Paste

The best CPU cooling paste for most gaming PCs is a reputable, electrically non-conductive compound such as Arctic MX-6, Noctua NT-H2, or Thermal Grizzly Kryonaut; choose liquid metal only when you accept greater installation risk for the lowest possible temperatures.

Thermal paste does not cool a processor by itself. It fills microscopic gaps between the CPU heat spreader and the cooler base, replacing air, which is a poor heat conductor. The best choice depends on your cooler, CPU power, installation method, maintenance plans, and tolerance for cleanup—not simply the largest conductivity number on the package.

ARCTIC MX-4 (4 g) - Premium Performance Thermal Paste for All Processors

Included for 'Best CPU Cooling Paste' because the listing specifies Premium Performance Thermal Paste for All Processors, details this guide uses to compare options.

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ARCTIC MX-7 (8 g) - Ultimate Performance Thermal Paste, Long Durability

Included for 'Best CPU Cooling Paste' because the listing specifies Ultimate Performance Thermal Paste and Long Durability, details this guide uses to compare options.

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ARCTIC MX-7 (4 g, incl. MX-Cleaner) - Ultimate Performance Thermal Paste

Included for 'Best CPU Cooling Paste' because the listing specifies incl. MX-Cleaner) and Ultimate Performance Thermal Paste, details this guide uses to compare options.

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ARCTIC MX-6 (4 g) - Ultimate Performance Thermal Paste for CPU, Consoles, Graphics Cards, laptops, Very high Thermal Conductivity, Long Durability, Non-Conductive

Included for 'Best CPU Cooling Paste' because the listing specifies Ultimate Performance Thermal Paste for CPU and Consoles, details this guide uses to compare options.

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Quick comparison: which paste fits your build?

Best overall: Arctic MX-6

Arctic MX-6 is a strong default for a new gaming build or a CPU repaste. It is electrically non-conductive, does not require curing, and is designed for both CPUs and GPUs. Its relatively thick consistency can help it stay in place, although it may require slightly more pressure than very fluid compounds.

Its advertised thermal conductivity is around 7.5 W/mK. That number is respectable, but it should not be treated as a direct prediction of CPU temperature. Manufacturers use different test methods, and the final result also depends on bond-line thickness, mounting pressure, cooler flatness, and the CPU’s integrated heat spreader.

Best for easy installation: Noctua NT-H2

Noctua NT-H2 is a forgiving, non-conductive paste that spreads reliably under cooler pressure. It is a practical choice when you want a clean installation and do not want to experiment with application patterns. It is suitable for air coolers and liquid coolers, from mainstream processors to high-power desktop chips.

NT-H2 is also sold in small cleaning-wipe kits, which can be convenient when replacing old paste. Its conductivity claim is lower than some premium competitors, but real-world differences between quality conventional pastes are often small—frequently around 1–3°C when the mounting process is equally good.

Best high-performance conventional option: Thermal Grizzly Kryonaut

Thermal Grizzly Kryonaut is aimed at high-performance systems and is widely used with powerful desktop CPUs, enthusiast air coolers, and liquid cooling systems. Its advertised thermal conductivity is approximately 12.5 W/mK, higher than many mainstream compounds.

Kryonaut is electrically non-conductive, so a small smear near the socket is less dangerous than liquid metal. However, it is not magic: a poorly mounted cooler can erase any advantage over a cheaper compound. Kryonaut is most worthwhile when the CPU regularly operates near its thermal limit or when you are tuning an overclock and want repeatable results.

Understanding thermal conductivity claims

Thermal conductivity, measured in watts per meter-kelvin, describes how readily a material conducts heat under a defined test condition. Paste packaging often highlights this figure, but it does not describe the entire CPU-to-cooler interface.

The relevant heat path can be simplified as:

Temperature rise across paste = CPU power × paste thermal resistance.

For example, suppose a 200 W processor has a paste layer with an effective thermal resistance of 0.05°C/W. The temperature difference across the paste is:

200 W × 0.05°C/W = 10°C.

If a better installation or compound reduces that resistance to 0.04°C/W, the difference becomes 8°C—a useful 2°C improvement. The calculation also shows why conductivity ratings alone are misleading. A thinner, more uniform layer can outperform a nominally higher-rated paste applied too thickly.

The cooler itself may contribute more thermal resistance than the paste. If the heatsink, fan curve, room temperature, or CPU voltage is the limiting factor, changing paste may produce only a modest improvement.

Electrical conductivity: conventional paste versus liquid metal

Most mainstream thermal pastes are electrically non-conductive. That does not mean they should be deliberately spread over the motherboard, but accidental contact is less likely to create a short circuit.

Liquid metal is different. Gallium-based products such as Thermal Grizzly Conductonaut and Conductonaut Extreme are electrically conductive. A spill can bridge contacts around the CPU socket, and a small amount can migrate during handling. Apply it only when the cooler and CPU are compatible and the surrounding area can be protected.

Liquid metal also chemically reacts with aluminum. Do not use it with an aluminum cold plate or aluminum heatsink surface. Copper and nickel-plated copper are normally the relevant compatible surfaces, but inspect the cooler’s specifications rather than guessing from its appearance.

How to apply thermal paste correctly

1. Remove the cooler without twisting aggressively

Warm the system first with a few minutes of normal CPU activity, then shut it down and disconnect power. Loosen the cooler gradually in a cross pattern. If the paste has hardened, gently rotate the cooler rather than pulling straight up, which reduces the chance of lifting the CPU from some socket designs.

2. Clean both surfaces

Use a lint-free cloth or coffee filter with high-concentration isopropyl alcohol. Remove all visible old compound from the CPU heat spreader and cooler base, then wait until the surfaces are dry. Do not use abrasive material that could scratch the contact surfaces.

3. Use an appropriate amount

For a typical desktop CPU, begin with a central dot about 4–5 mm across. For a large rectangular heat spreader, two short parallel lines or a small central cross can provide more consistent coverage. Do not manually spread a thick layer unless the paste instructions specifically recommend it; cooler pressure usually produces a thinner, more uniform film.

4. Mount once, evenly

Lower the cooler vertically if possible. Tighten screws in alternating diagonal steps until they are secure. Uneven pressure can create a hot corner even when the paste itself is excellent.

5. Recheck temperatures under the same conditions

Compare idle and load temperatures using the same room, power limit, fan curve, workload, and monitoring software. A change of 1–3°C can fall within normal measurement variation. More important signs of a successful repaste are reduced peak temperature, fewer thermal-limit events, or a lower fan speed at the same CPU power.

Application styles compared

Long-term stability and replacement intervals

Quality conventional paste commonly lasts several years in a desktop that is not repeatedly dismantled. Replace it when the cooler is removed, when temperatures rise without another explanation, or when the compound has visibly dried, separated, or pumped away from the center.

“Pump-out” occurs when repeated heating and cooling cycles push paste away from the hottest contact area. It is more likely with some thick compounds, uneven mounting pressure, or processors with concentrated hot spots. A paste with good stability can outperform a higher-conductivity compound that moves away from the die area over time.

Liquid metal may require more frequent inspection, especially after repeated transport or thermal cycling. It can stain or alloy with copper surfaces, and its performance depends heavily on maintaining a very thin, complete film. It is a specialist option rather than the default upgrade for a gaming PC.

Final recommendation

Choose Arctic MX-6 for the best all-round balance, Noctua NT-H2 for easy application and dependable maintenance, or Thermal Grizzly Kryonaut when you want a premium conventional compound for a high-power CPU. Use liquid metal only for a compatible copper or nickel-plated cooler when a small temperature advantage justifies conductive material and extra installation care.

Before buying the highest-rated paste, check the cooler mount, fan curve, CPU voltage, and case airflow. A secure mount and sensible power settings usually matter more than moving between reputable non-conductive compounds.