Thermal Grizzly Kryonaut Thermal Paste Review UK (2026)

Your CPU is hitting 95C under load, your cooler fan is screaming like a jet engine, and you're wondering if the problem is the paste or the cooler itself. Nine times out of ten, it's both. But here's the thing about thermal paste specifically: a bad application or a mediocre compound can cost you five to ten degrees even with a decent cooler mounted correctly. That's the difference between a chip that boosts freely and one that throttles the moment you push it. The Thermal Grizzly Kryonaut exists to close that gap, and with 62,313 averaging 4.7 stars, it's clearly doing something right.

The verdict first, because that's what you're here for: this is genuinely one of the best thermal pastes you can buy. The 12.5W/mK thermal conductivity figure is not marketing fiction, it's a real number that sits comfortably above most of the competition, and the non-conductive, non-capacitive formula means you're not taking risks with expensive hardware if you're slightly heavy-handed with the application. For anyone reseating a cooler on an Intel LGA1700 system, swapping paste on a console, or doing a proper GPU repaste, this is the compound to reach for. It's not the cheapest option on the shelf, but the 11.1g tube gives you enough for multiple applications, which changes the value calculation considerably.

What follows is a thorough look at what the specs and owner feedback actually tell us, because paste marketing is full of nonsense and someone needs to cut through it.

The compound is explicitly non-electrically conductive and non-capacitive, which matters more than people give it credit for. If you're repasting around the die on a GPU or working in a tight space on a console motherboard, a conductive paste that bridges contacts is a bad day. Kryonaut eliminates that risk. The viscosity is described as optimal for spreading, and owner reports back this up consistently: it's thick enough to stay where you put it but workable enough that a pea-sized blob spreads properly under cooler pressure without air pockets.

The 11.1g tube is the version covered here, and that's a meaningful quantity. A standard CPU application uses roughly 0.5g to 1g depending on method, so you're looking at ten or more applications from a single tube. For a repair shop or someone who regularly builds and services machines, that's a genuinely useful amount. The compound is suitable for CPUs, GPUs, and consoles according to the product listing, which is consistent with its thermal and electrical properties.

The viscosity is worth talking about because it genuinely affects how easy the paste is to work with. Too runny and it drips everywhere; too thick and you get air pockets and poor coverage. Owner reports consistently describe Kryonaut as sitting in a good middle ground: it spreads under pressure without being a mess, and it doesn't drip or run if you take a moment to position things before tightening the cooler down. The listing's claim about filling microscopic gaps is the right framing: thermal paste's job is to eliminate the air gaps between two imperfectly flat metal surfaces, and a compound that spreads evenly and stays put does that job well.

Thermal Grizzly as a brand has been in the PC cooling market long enough to have a track record. Their product line runs from Kryonaut (the mainstream high-performance option) up to Conductonaut and Carbonaut for specialist applications. Kryonaut sits at the sensible end of that range: high performance without the risks or complications of liquid metal. For GPU repasting specifically, where you're often working around small components and can't afford a conductive paste bridging anything, that's exactly the right call.

At 12.5W/mK, Kryonaut is doing a proper job of that gap-filling. Published independent thermal results from various sources consistently show Kryonaut performing within two to three degrees Celsius of the very best non-metal compounds available, and significantly better than budget or stock pastes. On a high-TDP chip like an Intel Core i9 or AMD Ryzen 9, where the heat spreader temperatures can hit 80C to 90C under sustained load, shaving even three degrees off that figure can mean the difference between the chip boosting freely and hitting its thermal limit and pulling back clock speeds. That's not a trivial gain.

For console repasting, which is a significant use case given the product listing explicitly mentions it, the performance argument is even stronger. PlayStation 4 and PlayStation 5 consoles in particular are known to run hot after years of use as the original thermal paste dries out and loses conductivity. Replacing it with a high-quality compound like Kryonaut is a well-documented way to bring temperatures down by meaningful amounts, and the non-conductive formula means there's no risk to the delicate circuitry around the APU. Owner reviews specifically mention console repasting as a successful use case, and the 11.1g quantity means you've got plenty for multiple consoles or a console plus a PC.

The practical consequence of switching to Kryonaut from stock paste or an older, degraded compound is that your cooler's fan curve gets easier to satisfy. If your CPU is running three to five degrees cooler at load, the fan doesn't need to spin as fast to maintain safe temperatures. On a well-tuned fan curve, that translates directly to lower noise at load. It's not dramatic in most cases, but if you're already close to your cooler's thermal ceiling, it can push you back into a quieter operating zone. Owners report this consistently: quieter fans after a repaste, particularly on laptops and consoles where the cooling solution is already working hard.

Worth being direct about something: thermal paste is not a magic fix for a fundamentally inadequate cooler. If your cooler is undersized for your CPU's TDP, better paste will help at the margins but it won't solve the underlying problem. What Kryonaut does is ensure the cooler you have is performing as close to its potential as possible. That's the right framing. And because it doesn't degrade as quickly as cheaper compounds (owner reports suggest it remains effective for several years), you're not looking at a situation where your noise levels creep back up after six months because the paste has dried out.

The one compatibility consideration is surface material. Kryonaut is safe on copper, aluminium, nickel-plated copper, and the standard heat spreader materials you'll find on consumer CPUs and GPUs. It's not a liquid metal, so there's no risk of it reacting with aluminium surfaces the way Conductonaut would. This makes it a genuinely safe choice for anyone who isn't confident about the materials they're working with. If you're repasting a GPU die that's exposed (some cards have no heat spreader), it's still safe to use.

The 11.1g quantity also has a practical compatibility advantage: you've got enough to experiment with application methods. Some people prefer the pea method (small blob in the centre, let the cooler spread it), others prefer a thin spread across the entire IHS. With 11.1g, you're not rationing. You can apply properly, check the spread if you want to by briefly mounting and removing the cooler, and reapply if needed. That's particularly useful for first-time GPU repasters who might want to see what coverage they're getting before committing.

For a standard CPU application, the pea method works well: a small blob roughly the size of a pea in the centre of the IHS, then mount the cooler with even pressure. The cooler's weight and mounting pressure spreads the paste as it seats. For larger IHS surfaces like Intel's LGA2066 HEDT chips or some AMD Threadripper processors, a thin spread across the surface before mounting gives better coverage. Owner reports suggest Kryonaut handles both methods without issue, spreading evenly without air pockets in either case.

For GPU repasting, the process is more involved because you're working with a bare die rather than a heat spreader, and the die is smaller and more fragile. The paste needs to be applied more carefully and in a smaller quantity. The good news is that Kryonaut's viscosity makes this manageable: it's controllable enough that you can apply a thin, even layer with a spreader or the edge of a card. Owner reviews from people who've repasted GPUs and consoles specifically mention that the paste behaves predictably and doesn't run or drip during application. The tube applicator gives reasonable control over the quantity dispensed, which helps.

The polymer-based formula is inherently more stable than some cheaper compounds that use carrier fluids which evaporate over time. The carrier fluid is what makes cheap pastes easy to spread initially, but as it evaporates the paste dries and cracks. Kryonaut's formulation doesn't rely on this approach, which is part of why it maintains performance over time. This is particularly relevant for console repasting, where the console might run for three to five more years after the repaste and you don't want to be pulling it apart again in eighteen months.

The tube itself is a standard syringe-style applicator, which is the right format for a product like this. It keeps the paste sealed between uses, prevents oxidation, and gives you control over how much you dispense. The 11.1g quantity means the tube isn't going to run out after two applications, which is a common frustration with smaller tubes. Owner reviews don't report issues with the tube sealing poorly or paste drying in the nozzle between uses, which is a practical quality-of-life point.

If you're building a system where the aesthetic of every component matters, the paste colour (a standard grey-silver) is consistent with every other thermal compound on the market, so there's nothing unusual to worry about. It won't stain surfaces dramatically if you get a small amount on the motherboard, though cleaning up any excess before it dries is always good practice. A cotton swab with a small amount of isopropyl alcohol handles any cleanup without drama.

The packaging is functional rather than flashy. The tube is clearly labelled, the Thermal Grizzly branding is present, and there's no elaborate box or accessories included. Some cheaper pastes come with a small spreader, and Kryonaut doesn't always include one depending on the version, but for most application methods you don't need one. The pea method requires no tools at all. If you're doing a spread application, a spare credit card or the edge of a piece of card does the job fine.

Console repasting is a recurring theme in the reviews, and the results people report are striking. PS4 Pro owners in particular mention temperature drops of ten degrees or more after replacing the original paste with Kryonaut, with fan noise dropping noticeably as a result. PS5 repasters report similar gains. This is consistent with what you'd expect: console paste is applied at the factory for cost efficiency rather than thermal performance, and it degrades over years of high-temperature cycling. A quality compound makes a real difference in that context.

PC builders report similar results. On high-end CPUs like the Ryzen 9 7950X or Intel Core i9-13900K, where the chips run hot by design and thermal headroom is tight, multiple owners report drops of three to eight degrees at load compared to their previous paste. That's within the range of what the 12.5W/mK rating would predict. Owners also note that the paste remains effective after two or three years, with temperatures not creeping up the way they do with cheaper compounds. That long-term stability is one of the strongest arguments for spending a bit more on quality paste rather than buying the cheapest option available.

For GPU repasting, Kryonaut is one of the recommended options specifically because it's not electrically conductive. GPU dies are exposed (no heat spreader on most discrete GPUs) and surrounded by VRM components and memory chips. A conductive paste in that environment is a genuine risk. Kryonaut eliminates that risk while still delivering high thermal conductivity. It's a sensible choice for anyone maintaining an older GPU that's running hotter than it should, or for enthusiasts who delid and repaste graphics cards as part of a performance optimisation project.

Consoles are the third major use case, and it's a good one. The paste is safe on the APU dies used in PlayStation and Xbox consoles, it handles the temperature cycling those systems go through, and the 11.1g tube is enough for multiple consoles. Repair shops in particular will find the larger tube format more practical than the smaller consumer-sized versions. If you're running a repair business and regularly repasting PS4s and PS5s, buying the 11.1g version makes more sense economically than buying multiple small tubes.

Where Kryonaut has a specific advantage is brand recognition and the trust that comes with Thermal Grizzly's reputation in the enthusiast community. The 62,000-plus reviews at 4.7 stars represent a level of owner validation that's hard to argue with. Arctic MX-6 is the value-oriented challenger: if you want the best performance per pound, MX-6 is. Noctua NT-H2 is the premium option if you want the highest rated conductivity figure and you're working with a chip that genuinely needs every degree you can get.

The one paste in a different category is Thermal Grizzly's own Conductonaut, which is a liquid metal compound rated at 73W/mK. That's a completely different product for a completely different use case: it's for delidded CPUs where the heat spreader has been removed and you're applying directly to the die. It's electrically conductive, it reacts with aluminium, and it requires significantly more care to apply safely. For the vast majority of use cases, including GPU repasting and console work, Kryonaut is the right choice and Conductonaut is overkill with added risk.

Who should buy this? Anyone reseating a cooler on a high-end CPU, anyone repasting a GPU or console, repair shops that go through paste regularly, and anyone whose current system is running hotter than it should after a few years of use. The 11.1g tube is particularly well-suited to anyone who does this work regularly, because you're not going to run out mid-job and you're getting better value per gram than the smaller tubes.

Who should skip it? If you're building a budget system with a stock cooler and a mid-range CPU, the paste that comes pre-applied on most coolers is good enough. You don't need to spend on premium paste for a Ryzen 5 7600 with a Noctua NH-U12S. The gains are real but small, and the money is better spent on the cooler itself. In that scenario, Arctic MX-4 or the stock application does a perfectly adequate job. Kryonaut earns its price on high-TDP chips, older systems being brought back to life, and any situation where the thermal interface is being worked hard.

If you want to spend less and still get excellent results, Arctic MX-6 is the honest budget recommendation. It's within a fraction of a degree of Kryonaut in real-world use and costs less per gram. But if you want the brand confidence, the larger quantity, and the proven track record that 62,313 represent, Kryonaut is the right call and you won't regret it.

Editorial score: 9 out of 10. It loses a point only because the price per gram is higher than the competition for essentially the same real-world performance. But as thermal compounds go, this is about as good as it gets without moving to liquid metal territory.