Review – Thermal Grizzly Kryonaut and Kryonaut Extreme Thermal Paste – A bit pricier, but what about the performance?

In this article, I will test the Thermal Grizzly Kryonaut and Kryonaut Extreme thermal pastes, which are the manufacturer’s top-of-the-line products and are recommended for use in extreme overclocking. The Kryonaut is available in quantities ranging from 1g to 37g, while the Kryonaut Extreme comes in sizes from 2g to 33.34g.

Both models of Kryonaut come packaged in the traditional “Zip Lock” packaging used by Thermal Grizzly products. The front of both packages prominently displays the product name, brand, and description, but the “Extreme” variant stands out with a transparent window. On the back, there is a list of the product’s characteristics written in ten different languages.

As for accessories, the 1g tube of Kryonaut comes with an instruction manual and an applicator spatula. For the 2g Kryonaut Extreme, the package includes an instruction manual, an authenticity verification card with a code that can be checked on the manufacturer’s website, and additional applicator tips.

It’s important to note that the purpose of thermal paste is to fill the tiny gaps between the heatsink and the CPU/GPU with a material that has better thermal conductivity than air, which helps to improve the heat transfer and ultimately reduces the temperature of the CPU/GPU.

According to Thermal Grizzly, Kryonaut has a thermal conductivity of 12.5 W/mk, while Kryonaut Extreme boasts 14.2 W/mk. Both pastes are suitable for use in extreme overclocking and can withstand temperatures ranging from -250 °C to +350 °C. This is no small feat, as modern CPUs and GPUs have higher thermal density and heat dissipation requirements, making it necessary to develop new compounds that can withstand the thermal stress without cracking when exposed to extremely low temperatures such as -190 °C.

However, it’s important to remember that being suitable for extreme use or having high thermal conductivity doesn’t guarantee outstanding performance and durability in everyday use, as these are very different usage conditions.

Applying the thermal paste is a very straightforward process, just follow the instructions provided in the manual and apply it to the Integrated Heat Spreader (IHS) of the processor. It’s worth noting that neither of the Kryonaut models are electrically conductive.

If you’re interested, here you can find links to the product pages for Kryonaut and Kryonaut Extreme on the manufacturer’s website. Now, let’s move on to the test configuration and the results obtained!

Hardware used:

CPU:AMD Ryzen 7 2700X (Thank you, AMD!)

MOBO: ASUS TUF X570-Plus Gaming (Thank you, Terabyteshop!)

RAM: 2×8 GB Crucial Ballistix 3200CL16

GPU: ASRock Radeon RX 5700 XT 8 GB

PSU: Seasonic SS-750AM

COOLER: XPG Levante 240 mm (Thank you, XPG!), Thermal Grizzly Carbonaut, IC Graphite, GD900-1, Deepcool Z3, Cooler Master Mastergel Maker, Thermal Grizzly Kryonaut, Thermal Grizzly Kryonaut Extreme.

SSD: Sandisk 120 GB

Software: Windows 10 x64, Blender 3.1.2, HWiNFO 7.26.

Testing Objectives:

The goal of these tests is to determine whether the Thermal Grizzly Kryonaut and Kryonaut Extreme thermal pastes can deliver good performance, and how they compare to other thermal interface alternatives that have been previously tested. The following texts contain more details about the methodology and how the tests were conducted.

Testing results:

In these tests, was used the Ryzen 7 2700X @ 4.1GHz 1.3375V LLC 3 and VDDSOC 1.025V, with memory set at 3200MHz XMP. We used Blender to render the “Classroom” demo for 30 minutes to obtain the results.

We tested the thermal paste immediately after application/cooling assembly and again in the next day, after a few “heat-cool” cycles, alternating between 40 minutes of idle and 40 minutes of stress in AIDA. The idea is to verify whether the thermal paste has any curing time, i.e., whether there is a difference in performance between the freshly applied product and the one that has undergone some thermal cycles.

The graphs below shows the delta T (ΔT), which is the difference between the CPU temperature (in this case) and the ambient temperature, thereby eliminating the ambient temperature from the equation.

In the end, both Kryonaut models performed the best right after application, with Kryonaut slightly outperforming its Extreme counterpart. However, after the “curing” process, both thermal pastes lost some performance, showing a difference of about 2 K compared to the initial test.

This is not an ideal result, as it raises questions about whether the performance loss will continue to increase over time. Some reports online suggest that this could indeed happen.


Both versions of the Thermal Grizzly Kryonaut performed very well when tested right after application, with the Kryonaut slightly outperforming its “extreme” counterpart and surpassing the Cooler Master Mastergel Maker by almost 2 K in this scenario. However, after some thermal cycles, also known as “curing time”, both versions of Kryonaut showed a decrease in performance, with an increase of about 2 K in delta temperature. This might not be very promising for long-term use in regular situations.

On the other hand, if the intention is to use it for extreme overclocking, past experiences have shown that Kryonaut is indeed an excellent option, with no issues such as cracking or the thermal paste limiting the maximum CPU frequency with LN2.

As for the cost, Kryonaut can be found for about 12 USD for a 1g tube and Kryonaut Extreme for approximately 30 USD for 2g. These are certainly high prices and can only be justified for extreme overclocking, where a larger quantity of thermal paste will be necessary than just 1g or 2g.

Special thanks to Thermal Grizzly for providing these samples for testing!

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