Thermal Paste, Pads and Compounds: Which One Should You Actually Use?

Thermal interface materials come in more flavours than most people realise — and picking the wrong one can cost you degrees you didn't need to lose.

Thermal interface material — TIM, if you want to sound clever in a Discord channel — exists for one reason: no two metal surfaces are ever perfectly flat. Zoom in far enough on your CPU's heat spreader and your cooler's cold plate and you'll find microscopic pits and peaks. Trapped air sits in those gaps, and air is a dreadful conductor of heat. TIM fills those gaps with something that shifts warmth far more efficiently than air ever could, giving your cooler a fighting chance at doing its job.

That's the whole game. Everything else — the silver particles, the graphene sheets, the eye-watering prices — is just different approaches to filling those gaps effectively and safely. So let's break down the three broad families, explain the conductive-versus-non-conductive question that trips everyone up, and then get into the specific products I'd actually recommend.

The Three Families of Thermal Interface Material

Before we talk brands, it helps to understand the categories, because each solves a slightly different problem. Get the category right and the specific product almost picks itself.

Conductive vs Non-Conductive: The Bit That Actually Matters

Here's the single most important thing in this entire article, and the reason I've seen more dead motherboards than I care to remember. Thermal materials fall into two electrical camps, and mixing them up can quite literally fry your hardware.

Non-Conductive (Ceramic, Silicone, Carbon-Based Pastes)

The overwhelming majority of consumer thermal pastes are electrically non-conductive. That means if you're a bit heavy-handed and squeeze a little onto a nearby capacitor or across the edge of the die, nothing catastrophic happens. Your temperatures might drift slightly, but your components survive. These are the pastes I recommend to everyone who isn't chasing world records — the Arctic MX-6, Noctua NT-H2 and Thermal Grizzly Kryonaut of the world all sit in this camp.

Electrically Conductive (Liquid Metal, Some Graphene Pads)

Liquid metal compounds — think gallium-based alloys — offer astonishing thermal performance. Products like Thermal Grizzly Conductonaut can drop temperatures by 10 to 15°C compared with standard pastes. But they're electrically conductive, they can corrode and damage aluminium, and a single stray droplet bridging two contacts can kill a board instantly. Some premium pads, like the graphene-based Thermal Grizzly Kryosheet, are also electrically conductive and must be fitted strictly to instructions.

Non-conductive pastes forgive the occasional smudge; liquid metal absolutely does not. Know which one is in your syringe.

Key Specifications at a Glance

When you're comparing thermal materials, a handful of figures do most of the heavy lifting. Here's what the standout products in this category bring to the table.

A quick word on those conductivity numbers, because they mislead people constantly. On paper, Kryonaut's 12.5 W/mK dwarfs the MX-6's 7.5 W/mK. In reality — as we'll see in the benchmarks — the temperature gap between them is a rounding error for most users. Thermal conductivity is a lab figure measured under ideal conditions, not a promise of how many degrees you'll drop on a Tuesday afternoon.

How They Actually Perform (Tested)

This is where theory meets the thermal probe. In my testing across identical mounting pressures and cooler setups, the pattern is remarkably consistent: modern premium pastes are separated by margins so small they barely register outside of a spreadsheet.

Most conventional pastes cluster within roughly 3°C of the venerable Arctic MX-4 under real CPU workloads. That's the headline finding, and it should change how you shop. The enduring MX-4 and NT-H1 class of pastes — supplemented by modern options like the MX-6 — remain more than adequate. They combine excellent viscosity, reasonable cost and perfectly acceptable thermals.

Look carefully at those bars. Against a nasty, dried-out stock paste, a quality premium compound genuinely earns you 10 to 15°C — that's a meaningful, worthwhile upgrade. But pit Kryonaut against the far cheaper MX-6 and the real-world difference collapses to somewhere between 0 and 2°C. For practical purposes, they perform identically. Meanwhile, the very best liquid metal on the market, Alphacool's Eisfrost Extreme, beats its nearest liquid-metal rival by a mere 0.5°C. The law of diminishing returns is brutal in this category.

The Sensible All-Rounder: Arctic MX-6

See Arctic MX-6 on Amazon UK
£6.99price at 10 Jul, may change

What I love about the MX-6 is that it just gets out of the way. The viscosity is spot-on — thick enough to stay put, thin enough to spread under mounting pressure without you having to fight it. It's available in a handy 2g tube for a single application, or a 4g tube if you're doing several builds. Against pricier rivals it holds its own beautifully: it's been measured as roughly 47% cheaper than Noctua's NT-H2 whilst landing within a couple of degrees of the premium pastes.

The Arctic MX-6 is the paste I keep coming back to — it does 95% of what the expensive stuff does for a fraction of the fuss.

The Premium Picks: Kryonaut, NT-H2 and Duronaut

Shop Kryonaut, NT-H2 and Duronaut on Amazon UK

If you genuinely want the last drop of performance from a non-conductive paste — or you just enjoy owning the good stuff — there are three names worth your attention.

Thermal Grizzly Kryonaut

The enthusiast darling. With 12.5 W/mK of conductivity and a frankly ludicrous -250 to 350°C operating range, Kryonaut is built for extreme cooling scenarios, including sub-zero overclocking runs where lesser pastes would crack. Testing has shown consistent 10 to 15°C improvements over dried-out stock pastes, and its real strength is consistency across different application methods and surface finishes — it's hard to get a bad result with it. The catch? It's roughly twice the entry price of the MX-6, and as we've seen, the real-world gap between them is 0 to 2°C.

Noctua NT-H2

See Noctua NT-H2 on Amazon UK
£11.95price at 10 Jul, may change

Noctua's engineering pedigree shines here. The NT-H2 offers 10 to 12 W/mK whilst staying electrically non-conductive, ships in a generous 3.5g tube, and includes three NA-CW1 cleaning wipes so you can prep your surfaces properly. It requires no burn-in period, delivers excellent temperature control that stays stable under prolonged heavy loads, and maintains its consistency over extended periods. It's around three times the price of the MX-6, and Noctua does charge a premium even for that already-large tube — but you're paying for a genuinely polished, no-drama experience.

Thermal Grizzly Duronaut

The newer performance play from Thermal Grizzly, the Duronaut was the best-performing thermal paste in my testing group. Beyond raw thermals, it's explicitly designed for long-term stability — the sort of paste you fit and forget. The downside is predictable: it's more expensive than its competitors, so it's a pick for people who value longevity and top-tier performance over saving a few pounds.

The Budget Champion: ID-Cooling Frost X45

Shop ID-Cooling Frost X45 on Amazon UK

The Frost X45 is proof that you don't need to spend big to get a good result. Given that most conventional pastes cluster within a few degrees of one another, the smart money on an air-cooled machine is often the cheapest paste that tests well — and this is that paste. I'd happily fit it in a family PC or a first-time build and not lose a wink of sleep.

The Extreme Options: Liquid Metal (Handle With Care)

Now for the dangerous end of the shelf. Liquid metal is where the biggest raw thermal gains live — but also where the biggest risks hide.

Alphacool Eisfrost Extreme

If you want the best-performing liquid metal available, bar none, this is it. In testing the Eisfrost Extreme outperformed its competitors by 0.5°C — a small margin, but at the very top of the performance curve every fraction counts. For extreme overclockers and delidded CPUs, it's the pick to beat.

Thermal Grizzly Conductonaut

The famous name in gallium-based compounds. Liquid metals like Conductonaut can slash temperatures by 10 to 15°C compared with standard pastes — a huge leap. But, and it's an enormous but, they're electrically conductive and can damage aluminium components through corrosion. This is not paste you apply casually.

Pads and Sheets: Kryosheet and Where Pads Belong

Thermal pads deserve their own conversation because they solve a problem pastes can't. When you need to bridge a larger or uneven gap — over VRMs, VRAM chips, or between a GPU die and a backplate — a paste would simply squeeze out or fail to make contact. Pads, combining silicone or polyurethane with ceramics, graphite or metallic oxides, hold their shape and stay put. Most are thermally conductive but electrically insulating, which makes them safe around dense circuitry.

Thermal Grizzly Kryosheet

The premium, headline-grabbing pad. The Kryosheet is a graphene sheet just 0.2mm thin, with its molecular structure stacked in the Z-direction for outstanding and consistent thermal conductivity. Thermal Grizzly achieves this through a specially developed process in which the hexagonal crystal structure of graphite is broken up along the basal plane. It comes in a wide range of pre-cut sizes — from a tiny 24 × 12mm right up to a chunky 75 × 72mm — so you can match it to almost any component.

The appeal of a graphene sheet like this is reusability and longevity — it doesn't dry out or pump out over time the way a paste eventually will. For someone who reseats their cooler often, or who simply hates the mess of paste, it's a genuinely interesting proposition, provided you respect the electrical-conductivity warning.

Graphene sheets like the Kryosheet never dry out — but their electrical conductivity means careful placement is non-negotiable.

The High-TDP Specialist: Corsair XTM70

See Corsair XTM70 on Amazon UK
£14.99price at 10 Jul, may change

Which Should You Use? By Machine Type

Let's turn all of this into concrete advice, because the right choice genuinely depends on what you're cooling.

Gadget Scout Rating

Scoring an entire category is a slightly odd exercise, so what I've rated here is the state of the thermal-interface market as a whole in 2026 — how well it serves buyers across price points, performance and safety. The short version: it's never been a better time to buy, because the cheap stuff is genuinely excellent.

The safety score takes a small hit purely because liquid metal and conductive graphene pads exist and are all too easy for beginners to misuse. Everything else scores highly — and value in particular is exceptional, because a sub-£10 paste like the Frost X45 or the MX-6 will serve the overwhelming majority of builders beautifully.

Frequently Asked Questions