AMD has revealed its new "Zen 5" architecture, which includes the powerful Ryzen 9 9900X. This 12-core, 24-thread CPU is built on a 4nm process and is likely to be a favorite among high-end PC builders, gamers, and overclockers. That means the AMD Ryzen 9 9900X needs (and deserves) the best thermal paste money can buy. Here are our top recommendations for your build.

  • Best overall
    Arctic MX-6
    Electrically conductive
    No
    Density
    2.6 g/cm³
    Viscosity
    45,000 Poise
    Operating temperature
    -50~150 ℃
    Color
    Grey
    Price per gram
    $2.12

    If you're looking for the best thermal paste and don't want to think too hard about it, just get some Arctic MX-6 and call it a day. It's highly effective, priced right, and delivers up to 20% more thermal efficiency than its popular predecessor, the Arctic MX-4 paste.

  • Runner-up
    Noctua NT-H1
    Electrically conductive
    No
    Density
    2,49 g/cm³
    Operating temperature
    -50 to 110°C
    Color
    Grey
    Recommended usage time (on the CPU)
    up to 5 years
    Volume
    1,4 ml

    The Noctua NT-H1 thermal paste is another excellent option that performs about as well as the Arctic MX-6. It's also rated to last for around five years and has no break-in period, so it's ready to go as soon as it's applied. The only reason it's not our top pick is that it's a little more expensive per gram than the MX-6.

  • Best value
    Arctic MX-4 GPU Thermal Paste

    Don't want to spend more than a few bucks, and just need a thermal paste that's cheap and effective? You can't go too wrong with the Arctic MX-4, which has been a standby for builders for more than a decade. There are more efficient choices for applications such as overclocking, but the MX-4 is more than sufficient for most needs.

  • Premium pick
    Thermal Grizzly Kryonaut Extreme

    If you do intend to overclock your Ryxen 9 9900X CPU, the Thermal Grizzly Kryonaut Extreme is an enthusiast-tier thermal paste worthy of a high-end PC build. It's a little pricey, but offers some of the best performance on the market, with a thermal conductivity of 14.2W/mK. It's the best choice for overclockers.

  • Best thermal pad
    Thermal Grizzly Carbonaut
    Thermal conductivity
    62.5 W/mk
    Electrically conductive
    Yes

    The Thermal Grizzly Carbonaut is an interesting and effective alternative to pastes. It's pre-cut to fit the CPU die, which takes the guesswork (and mess) out of the application. While the Carbonaut thermal pad is a bit expensive compared to most thermal pastes, you can reuse it if you ever need to swap out your CPU.

  • Beginner-friendly
    Corsair XTM70 Extreme

    If it's your first build and you're not used to applying thermal paste, the Corsair XTM70 makes it all but foolproof. This high-performance thermal paste includes a handy installation kit with a stencil that ensures a perfect spread. Plus, the paste itself is efficient enough for applications like overclocking.

  • For liquid cooling
    Thermal Grizzly Hydronaut
    Thermal conductivity
    0.0076 K/W
    Electrically conductive
    No
    Viscosity
    140-190 pas

    If you're running a liquid-cooled setup, Thermal Grizzly makes a paste for that. The Hydronaut is a metal-based compound instead of silicone, so it's easy to spread and includes an applicator to make things even easier. It's also a cost-effective option for overclocking, which you're likely doing if using a liquid cooler. Keep in mind that this compound is conductive, so use with care.

  • Easy application
    Cooler Master MasterGel Regular
    Thermal conductivity
    5 W/mk
    Electrically conductive
    No
    Density
    2.5 g/cm³
    Color
    Grey

    The Cooler Master MasterGel comes in a flat-nozzled syringe, which makes application so easy that you'll wonder why all pastes don't copy this design. This means you don't have to mess around with a scraper or other applicator to spread it evenly.

  • Best liquid metal
    Thermal Grizzly Conductonaut

    Most thermal pastes are non-conductive for safety reasons. The Thermal Grizzly Conductonaut is one of the few available liquid metal thermal pastes that is conductive, and because it's a liquid, it takes some care to apply. However, it's an excellent thermal solution for high-end builds and overclockers who know what they're doing. Just remember: you can't use this thermal paste with aluminum heatsinks.

Which thermal paste should you buy for the AMD Ryzen 9 9900X?

Admittedly, which thermal paste to use isn't close to being the biggest decision you'll have to make when building a PC. In fact, your thermal paste won't make a huge difference. That's not to say it doesn't make any difference, however. For high-end PC builds, especially those running a premium CPU that allows for overclocking (as the Ryzen 9 9900X does), a few extra percentage points of thermal efficiency can matter.

For most builds, the best thermal paste for the AMD Ryzen 9 9900X is Arctic MX-6. This is the one to buy if you want a great, inexpensive thermal paste and don't want to think too much about it (which, as we said, you don't usually have to with thermal paste). If you want something even cheaper and you're not planning to do any overclocking, the Arctic MX-4 is another excellent option. Our budget pick is an old standby that's been in service for more than a decade, so it's tried and trusted.

If you plan to overclock your Ryzen 9 9900X, consider investing in something a little beefier. In that case, the Thermal Grizzly Kryonaut Extreme is worth the upgrade. It's not cheap as far as thermal paste goes, but its 14.2W/mK thermal efficiency is top-notch. It's also easier and safer to use than other enthusiast-grade thermal pastes, like the liquid metal Thermal Grizzly Conductonaut.

👁 An image showing thermal paste being applied on an Intel Core i7-14700K CPU.
How to apply thermal paste to a CPU

Applying thermal paste to the CPU is a crucial step, but it's a fairly simple task.