Our editors independently research, test, and recommend the best products; you can learn more about our review process here. We may receive commissions on purchases made from our chosen links.
Best Overall: Arctic MX-4 at Amazon
"Practical, affordable in its 4-gram quantity, and at a purported eight-year lifespan, is one of the longest-lasting thermal pastes around."
Runner-Up, Best Overall: Noctua NT-H2 at Amazon
"Not electrically conductive, NT-H2 can be used with any type of heatsink, whether it’s copper or aluminum."
Best Silver Compound: Arctic Silver 5 at Amazon
"Because silver is the most thermally conductive metal, you can get stellar cooling results from an affordable package."
Best for Advanced Users: Thermal Grizzly Conductonaut at Amazon
"Boasting a whopping 73 W/mK of thermal conductivity, it’s the go-to product for heavily overclocked CPUs."
Best Budget: ThermalCoolFlux 5-Pack at Amazon
"Available in a five-pack of syringes, each containing 1.5 grams of the compound. That adds up to a lot of value."
Best for Sub-Zero Setups: Thermal Grizzly Kryonaut at Amazon
"Made of nano-aluminum and zinc-oxide particles, is designed to work in the coldest environments without drying out."
Best Thermal Pad: Graphite Thermal Pad at Amazon
"Rated for thermal conductivity of 35 W/mK and a temperature range between -200 and 400 degrees Celsius, they are plenty effective for most situations."
The main goal of any thermal interface material (TIM) is simple: Fill the microscopic gaps between your processor or graphics card and the heatsink of your cooler, so it can cool your CPU or GPU more efficiently. By that token, the Arctic MX-4 Thermal Compound doesn't disappoint. Along with numerous other benefits, it serves as an excellent all-around choice.
First and foremost, Arctic MX-4 provides superb performance. Made up of carbon micro-particles, its thermal conductivity is rated at 8.5 watts per meter-kelvin (W/mK), which means it’s excellent at transferring heat. At the same time, the carbon-based compound doesn’t conduct electricity, so you don’t have to worry about damaging your system if it spills over onto other components.
It also helps that Arctic MX-4 is practical, affordable in its 4-gram quantity, and at a purported eight-year lifespan, is one of the longest-lasting thermal pastes around. Its consistency is so moderate it doesn’t need time to cure or set. Whether or not you use the included spreader tool, it’s easy to apply as well, even for novices. This isn’t just a matter of convenience — proper TIM application can make a visible difference, too.
Noctua’s original NT-H1 was highly regarded for being an effective, premium thermal paste at an affordable price. With the NT-H2 compound, the trusted cooling-focused company has improved on the formula, creating a new mix of metal oxide micro-particles that could make CPU temperatures cooler than ever. The new generation comes at a bit of an additional cost, but the upgrade can be well worth it for people looking to get a performance edge out of their CPUs, especially when overclocking.
Not electrically conductive, NT-H2 can be used with any type of heatsink, whether it’s copper or aluminum. The generally recommended method of thermal paste application, which involves placing a small drop to the middle of the CPU and securing the cooler on top (rather than manually spreading), works well here. Noctua even includes a few of its own cleaning wipes with isopropyl alcohol to safely wipe off and reapply the compound when necessary.
Arctic Silver 5 is a popular and widely used thermal paste, and for good reason. The compound includes particles of 99.9 percent pure silver. And because silver is the most thermally conductive metal, you can get stellar cooling results from an affordable package.
The downside, however, is that silver is also highly conductive of electricity, running the risk of short-circuiting other hardware with which it gets into contact. Arctic Silver 5, though, is essentially a ceramic compound and not electrically conductive. It is still slightly capacitive, so it should be kept away from electrical pins and paths as much as possible.
In terms of usability, Arctic Silver 5’s three-phase viscosity makes application simple. It comes out of the syringe smoothly, thins out to fill the tiny air pockets on the CPU surface, and then thickens slightly for long-term stability. This subtle process does take more time to settle in than other pastes, so Arctic Silver suggests waiting up to 200 hours until it reaches its full conductive potential.
Among most of the standard thermal greases and pastes, the differences in pure thermal conductivity aren’t huge. But enter the realm of liquid-metal compounds like Thermal Grizzly’s Conductonaut and you start to see a much more significant gap. Boasting a huge 73 W/mK of thermal conductivity, it’s the go-to product for heavily overclocked CPUs, where you’re drawing out maximum performance and scorching temps. While traditional, non-metallic compounds typically fall within a few degrees of difference in cooling power, Conductonaut’s mixture of gallium, indium, and tin has the potential to cool your system down by an extra 10 degrees or more.
On the flip side, the very real power of liquid metal comes with very real risks that call for a lot of caution. One is that it can’t be used with aluminum heatsinks, since the gallium can damage and blacken the aluminum. Liquid metal pastes are also electrically conductive, so any spills can short circuit and destroy surrounding components. Unfortunately, the material tends to squirt out of the syringe, and its thinner consistency lets it run off surfaces more easily than traditional pastes. You’ll want to apply Conductonaut extremely carefully and properly safeguard neighboring hardware to prevent these small tragedies.
It has been said that you can use toothpaste as a makeshift thermal material, but with so many low-priced TIMs out there, there’s no justifiable reason to take the risk. ThermalCoolFlux thermal paste, for example, is available in a five-pack of syringes, each containing 1.5 grams of the compound. That adds up to a lot of value for a product from which you can get a lot of mileage, especially if you don’t use up a full syringe on a single application. Plus, the separate containers result in a better storage life than a single large tube, letting you keep them fresh until you need them. It makes it easy to have some on-hand for quick fixes.
ThermalCoolFlux is described as a “silver-color” polysynthetic thermal paste, without a detailed list of materials, but it’s pretty safe to assume it doesn’t include higher-end pure silver particles. Still, its listed 3.2 W/mK of thermal conductivity certainly represents solid performance for minimal cost.
For extreme cooling setups that use sub-zero temperatures to overclock CPUs and GPUs to the max, not just any thermal paste will do. Your TIM needs to be able to transfer a lot of heat, but metal-based compounds aren't designed to hold up in freezing conditions. The Thermal Grizzly Kryonaut, made of nano-aluminum and zinc-oxide particles, is designed to work in the coldest environments without drying out. It can also take on plenty of heat, as it’s able to handle temperatures between –250 and +350 degrees Celsius.
The non-electrically conductive or capacitive paste is an excellent performer in general, even if you’re not overclocking your components in the extreme cold. Its thermal conduction rated at 12.5 W/mK offers what may be the best heat transfer results among non-metallic thermal materials on the market. It comes in a 1-gram syringe with an included spreader, and with no curing time needed, the application processs is quick and painless.
Since thermal pads as a whole aren’t as effective at keeping your components cool, they tend not to be recommended over thermal pastes for serious PC cooling setups. But if you’re looking to take advantage of the benefits they do offer, a graphite thermal pad from Innovation Cooling is a smart way to go.
Rated for thermal conductivity of 35 W/mK and a temperature range between -200 and 400 degrees Celsius, Innovation Cooling’s pads are plenty effective for most situations. Compared to paste compounds, they’re much more simple to apply, with little room for error. Available in 30x30mm or 40x40mm flavors, each tailored to a different chip size, set one on top of a clean CPU or GPU surface, mount the heatsink, and the application is complete.
The pads are electrically conductive, but since they’re not a liquid metal that can pervade other of your computer, you’re unlikely to inadvertently damage other components. Plus, not only are they mess-free, but they’re reusable for your future builds as well.