Best Thermal Paste 2026: Kryonaut, Kryonaut Extreme… Which One for Your CPU and Graphics Card?

Good news for your wallet: among good thermal pastes, independent tests measure differences of around 1 °C, sometimes less. The brand matters far less than how you apply it and how good your cooler is. Here are our picks by use case, with prices checked on October 11, 2026:

• Tight budget or first build: Arctic MX-4 (4 g) — No current US offer. In Tech4Gamers’ test, it finishes just 1.5 °C behind the best paste and 1.1 °C behind the Noctua NT-H2.
• Best value per gram: Arctic MX-6 (8 g, No current US offer) or Noctua NT-H1 (3.5 g, No current US offer).
• The enthusiasts’ benchmark: Thermal Grizzly Kryonaut — No current US offer (1 g tube) / No current US offer (5.55 g).
• Extreme overclocking (liquid nitrogen): Kryonaut Extreme — No current US offer (2 g). Pointless for a regular gaming PC.

Fitting a new CPU cooler? Start with our guide to choosing a CPU cooler: better cooling wins you far more degrees than a pricier paste.

We only kept measurements published with their test conditions. No temperature is extrapolated.

• Tech4Gamers (May 2024), 8 pastes on a Ryzen 7 7700: CPU locked at 5.2 GHz and 1.33 V (105 to 110 W), cooled by an Alphacool Eisbaer Pro Aurora 360 AIO with pump and fans at full speed. Maximum temperature under stress: 59.4 °C with the Noctua NT-H2, 59.9 °C with the Kryonaut and 60.5 °C with the Arctic MX-4. The best paste in the test (Thermal Hero Quantum, 59 °C) and the fourth are only 1.5 °C apart.
• EnosTech, Arctic MX-6 vs Noctua NT-H1: the MX-6 lowers temperatures by 1 °C compared with the NT-H1, which the site uses as the reference paste on its bench. The tester calls the gap “barely” significant.
• Igor’s Lab, Kryonaut vs Kryonaut Extreme: measured in the lab, the two pastes are “de facto tied” at thicknesses of 25 to 150 µm, the range of a normal CPU install. The Extreme remains a paste designed for very low temperatures.

Bottom line: for a gaming PC, the cheapest paste in this roundup does almost as well as the most expensive one. What really matters is the air cooler or AIO, the right amount of paste and proper mounting pressure.

Many roundups rank pastes by their thermal conductivity in W/mK. The problem: these figures aren’t measured the same way, and manufacturers don’t always publish them.

• Thermal Grizzly used to quote 12.5 W/mK for the Kryonaut and 14.2 W/(m·K) for the Kryonaut Extreme (spec sheet reported by Guru3D in December 2020). The brand’s current product pages and datasheets no longer list a W/mK value (checked on October 11, 2026).
• Arctic refuses to publish a value: the brand explains that thermal paste sits between 1 and 4 W/mK and that figures like 12.5 W/mK “do not correspond to the truth”.
• Noctua doesn’t give a conductivity figure for its NT-H1 and NT-H2 either.
• In the lab, Igor’s Lab measured an effective conductivity of 4.264 W/(m·K) for the Arctic MX-6 under the ASTM D5470 standard.

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A syringe of Thermal Grizzly Kryonaut — photo Jacek Halicki, CC BY-SA 4.0, via Wikimedia Commons.

So go by measured temperatures rather than the W/mK printed on the box. If a roundup promises you 3 to 5 °C better thanks to a higher conductivity figure, with no test to back it up, be wary.

Sources: Thermal Grizzly product pages and datasheets, Arctic (MX-6 page and FAQ) and Noctua; Guru3D (December 2020); Tech4Gamers (May 2024), EnosTech and Igor’s Lab tests, checked on October 11, 2026. Prices: on October 11, 2026, none of the Thermal Grizzly pastes had a US offer in the DropReference catalog, and Arctic and Noctua aren’t in our catalog yet (checked on October 11, 2026), so we show no dollar price rather than converting euros. Prices may have changed since.

The Kryonaut is the paste you see most often in high-end PCs. According to its datasheet, it doesn’t start drying out at 80 °C, it isn’t electrically conductive (0 pS/m), it works from −250 °C to +350 °C and it comes in four sizes: 1 g, 1.5 ml (5.55 g), 3 ml and 10 ml.

In Tech4Gamers’ test, it finishes 0.5 °C behind the NT-H2 and 0.6 °C ahead of the MX-4, for a much higher price per gram. The 1 g tube is enough for one build: No current US offer as of October 11, 2026 (DropReference catalog). If you swap coolers often or have several PCs, the 5.55 g size: No current US offer (DropReference catalog).

On Amazon, Kryonaut listings bundle several sizes under titles that don’t match the chosen product, so we show our DropReference catalog listings instead.

The Kryonaut Extreme (pink, 3.76 g/cm³) uses finer particles and is aimed first at liquid-nitrogen overclocking. Thermal Grizzly presents it as a paste for very low temperatures, but also for watercooling. It comes in 2 g, 6 g and 9 ml (33.84 g).

For a gaming PC, its results don’t justify the price gap: Igor’s Lab puts it on par with the regular Kryonaut at normal mounting thicknesses. The 2 g size: No current US offer as of October 11, 2026 (DropReference catalog; no dollar price shown). The 33.84 g tub, No current US offer (DropReference catalog), is meant for overclockers and workshops.

The MX-4 is the budget paste par excellence: No current US offer for the 4 g tube as of October 11, 2026. Arctic says the formula hasn’t changed despite the new packaging. In Tech4Gamers’ test, it finishes just 1.1 °C behind the NT-H2.

The MX-6 succeeds it. According to Arctic, its thermal resistance is measurably lower than the MX-4’s (“20%” better, measured by the brand on its lab machine). It is very viscous (45,000 poise) and doesn’t spread with a spatula: the cooler’s mounting pressure spreads it. The 8 g tube: No current US offer as of October 11, 2026.

The NT-H1 doesn’t need spreading: you put the paste down and the cooler spreads it. Noctua says it keeps for at least 3 years at room temperature and can stay 5 years or more on a processor. The 3.5 g tube is enough for 3 to 20 applications depending on CPU size. Price: No current US offer as of October 11, 2026.

The NT-H2 is its second generation, with a new blend of metal-oxide micro-particles according to Noctua. At Tech4Gamers it comes second (59.4 °C), behind only the Thermal Hero Quantum and ahead of the Kryonaut. We don’t show it as a block: the Amazon listing we found has a wrong title (“0.1 g”) that doesn’t match the 3.5 g tube.

Good to know: recent Noctua coolers ship with paste, like the NH-D15 G2 in our Ryzen 7 9800X3D cooler guide.

On a desktop processor, the paste sits between the CPU’s metal lid (IHS) and the base of the cooler. On a graphics card there is usually no lid: the paste touches the GPU die directly.

• Pick an electrically non-conductive paste: every one in this guide is. Avoid liquid metal on a graphics card unless you know exactly what you’re doing.
• Before taking a graphics card apart, check its warranty: some manufacturers refuse it if the card has been opened.
• For a GPU repaste, a bigger size (Kryonaut 5.55 g, MX-6 8 g) keeps you from running short, since the die must be fully covered.

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A stock Intel cooler with its pre-applied paste (grey, on the copper base) — photo Ashley Pomeroy, CC BY 4.0, via Wikimedia Commons.

The pre-applied paste on a stock cooler or an AIO is generally fine for a first build. You only replace it if you remove the cooler. To compare AIOs, read our AIO liquid cooler comparison.

• Remove the cooler or AIO after a few minutes of use: warm paste comes off more easily.
• Wipe off the old paste with a lint-free cloth and isopropyl alcohol, or the brand’s own cleaner (Arctic sells an MX Cleaner).
• Put a small amount in the center of the processor. With an MX-6 or NT-H1, don’t spread it: the cooler’s pressure takes care of it.
• Refit the cooler, tightening the screws crosswise, a little at a time, then check temperatures under load.

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A removed cooler with the old thermal paste still on its base — photo Mattes, CC BY-SA 2.0, via Wikimedia Commons.

If your temperatures stay high after a repaste, the problem often lies with the cooler itself. For a Ryzen 7 9800X3D, check our air cooler and AIO comparison for the 9800X3D.

Is the Kryonaut worth the price?

For an enthusiast, yes: it’s among the front-runners in tests. But the measured gap with an MX-4 is only 0.6 °C at Tech4Gamers, for a much higher price per gram.

Kryonaut or Kryonaut Extreme?

The regular Kryonaut. Igor’s Lab measures the two pastes as tied at normal mounting thicknesses; the Extreme is designed for liquid nitrogen.

Which cheap thermal paste should I choose?

The Arctic MX-4 (4 g), the cheapest paste in this roundup in Europe; on October 11, 2026 there was no current US offer in our catalog. For more paste, the MX-6 comes in an 8 g tube.

Should you change your thermal paste regularly?

Not without a reason. Noctua claims 5 years or more on the CPU for the NT-H1, and the Kryonaut’s datasheet says it doesn’t start drying out at 80 °C. Change it when you remove your cooler or if temperatures rise with no other explanation.

For a gaming PC, get an Arctic MX-4 (No current US offer) or an MX-6 (No current US offer): tests show only about 1 °C of difference from premium pastes. If you want the easiest paste to apply and the longest-lasting, choose the Noctua NT-H1 (No current US offer). The Kryonaut (No current US offer for the 1 g tube) remains the enthusiasts’ benchmark, and the Kryonaut Extreme (No current US offer for the 2 g) is for extreme overclocking only.

Prices checked on October 11, 2026: DropReference catalog (no US offer for any paste in this guide); Amazon blocks for Arctic, Noctua and the Kryonaut Extreme 2 g.