Polartherm X8 and Polartherm X10 Thermal Paste Review – New brand, good price and decent performance for the money

1 - Introduction, overview and pricing 2 - Single test of the Polartherm X8 3 - Single test of the Polartherm X10 4 - 1:1 comparison of the two pastes (and others) 5 - Maturing and degradation 6 - Summary and conclusion

Thermal Grizzly, best known as a specialist for premium thermal pastes and various cooling accessories, has launched a new brand, Polartherm, which focuses purely on the mid-range and entry-level segment with the already affordable X10 and the even more affordable X8. The aim is to establish a contemporary product line that offers solid performance at a more affordable price and is, so to speak, the little brother of the rather expensive high-performance pastes, about which I will have to say a word later, because new brooms sweep better, as we all know. And that’s exactly why Thermal Grizzly already has an update for the higher-priced products firmly in mind, because at least the X10 is already showing very cannibalistic traits in its own haze. I won’t spoil any more at the beginning, because I’ll get to that in a moment.

With this strategy, Thermal Grizzly wants to appeal to all those who want reliable cooling performance but don’t want to go to great (and financial) lengths to tease out the last (half) degree Celsius. While the tried and tested pastes such as Kryonaut and Conductonaut are intended for overclocking enthusiasts and power users, Polartherm offers an everyday solution for gamers and PC tinkerers who simply want a cool CPU without having to dig deep into their pockets. Thermal Grizzly thus remains true to its mission of offering the right product for almost every requirement – be it absolute top performance or a high-performance solution with a certain touch of understatement, as Polartherm is supposed to offer. With a wink, you could say: Polartherm offers cool CPUs without a high price. Or full cooling at half the price, or…

Incidentally, the term Polartherm definitely has something amusing about it if you think about it more closely. It is made up of the words “polar” and “therm”, which at first glance conjures up two rather contradictory images. “Polar” is reminiscent of the extreme temperatures of the Arctic and Antarctic – icy, freezing cold that is more likely to cause frostbite than warmth. “Therm”, on the other hand, comes from the Greek and stands for warmth or heat. If you combine these two elements, you get a paradoxical-sounding mixture of “icy heat” or “warming cold”. Sounds kind of contradictory, doesn’t it? But that was already the case with the thermal grizzly instead of the polar bear and it is now difficult to register anything suitable as a trademark without any problems.

And that’s exactly what makes it funny again: it suggests a solution that manages to tame the hottest heat with the coolest precision. It’s a cleverly constructed name that charmingly conveys the idea of cooling heat dissipation and at the same time plays a little with linguistic irony. Ok, so far, so verbal. And how does the whole thing actually cool? I’ll find out in the lab, of course, and in addition to playing around with the temperatures, I also tested some ageing and how the pastes really behave when heated. This, in turn, is definitely only available here.

Polartherm X8 or X10? How much of what or of each?

The new top model in Polartherm’s “budget” line is the X10 with a bulk thermal conductivity of around 3.8 W/m-K, as measured by me. This value is, of course, to be seen in relative terms, but it already represents a very solid mid-range model. Incidentally, these are authentic measured values from my laboratory and I have written more than once that many of the competitors’ fabulous values are unfortunately just pure marketing and brazen lies. Let me reiterate this in advance, because even very good and expensive industrial pastes are still well below 6, usually only 4.5 to 5.3 W/m-K. Just to put the real measured values into context.

Much more interesting than the bulk value, however, is the low interface resistance, i.e. the heat transfer resistance between the paste and the two thermally connected surfaces. At 6.2 mm²-W/K, this is far better than the average and is really pleasantly low. Conversely, this means that pastes with perhaps a better bulk value for thermal conductivity could stumble over their often significantly higher interface resistance, especially with thinner layers. Polartherm has achieved a pretty good compromise here between user-friendliness, performance and effort (filling, mixing).

The Polartherm X8 is a very similar paste that uses identical siloxanes, but is filled slightly lower with thermally conductive particles and a different mixing ratio of these powders of aluminum oxide and zinc oxide. The paste is significantly more fluid, but already tends to pull threads and has a less high-quality appearance overall. It is very easy to handle for first-time users and newcomers, although the performance and durability are of course lower than those of the X10. Incidentally, the price does too, which puts this into perspective. Let’s call it a good beginner’s paste, because with a bulk thermal conductivity of around 3 W/m-K and a slightly higher interface resistance of 7.1 mm²-K/W, the paste still lags somewhat further behind the X10 than the price advantage might suggest. But in the end, everyone has to decide for themselves.

Polartherm offers a fairly wide range of packaging and containers, from economical 2 gram, 5 and 10 gram to 40 gram family packs for both pastes. This has its charm, even if it is quite a lot of choice with only two pastes. But it’s better than just either or. It works, especially as the outer packaging is not made of plastic. It’s more sustainable and also saves the manufacturer from having to deal with the authorities, because you don’t have to register or declare every little thing.

Speaking of economical, the RRP is a small but very pleasant surprise, even if Roman is of course not Father Teresa. But at least they don’t go all Unilever on us here, but keep the price down to earth, which is not at all a matter of course in this day and age of shrinkflation and price increases via “new formulations”.

Let’s now turn to the measurements and if you want, you are welcome to find out more about the basics and the test setup:

Test setup and methods	Material analysis and microscopy	Basic knowledge
Here you can find out why effective thermal conductivity and bulk thermal conductivity can be completely different in practice, what role the contact resistance between the surfaces and the paste plays and how thermal paste can be measured accurately. There is also a detailed description of the equipment, the methodology and the error tolerances.	You will learn how laser-induced plasma spectroscopy works and the advantages and limitations of the measurements. There is also high-resolution digital microscopy and analysis of particle sizes. This information is also used to estimate the long-term stability of a paste.	Anyone who has always wanted to know what is or is not in a paste and how these pastes are produced will find what they are looking for here. The basic article provides a better understanding of what is often sold for far too much money and sometimes with adventurous promises.