Custom loops depend on good contact between the chip and its cold plate, so paste choice still matters after you have selected the rest of your cooling hardware. The Best Thermal Pastes for Water Cooling below favor stable, practical compounds for CPUs and GPUs. Learn how to repaste a CPU before starting the job.

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Kingpin Cooling KPx Thermal Paste 3g

Size 3 grams
Product Group Personal Computer
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Built around a compact 3g format, Kingpin Cooling KPx Ultimate Performance Thermal Paste is listed for cooling-compound applications where a fresh supply is needed. It appears in the Silicon Grease category, but the available product data does not state its thermal conductivity or electrical-conductivity behavior. That makes it a clearer choice for shoppers who already know the KPx line and want the 3g size than for buyers comparing published material specifications. Its Ultimate Performance naming suggests a performance-oriented positioning, though the listing provides no technical figures to verify or compare that claim.
Pros & Cons
Reasons to Buy
  • Compact 3g size is clearly identified
  • Recognizable Kingpin Cooling branding
  • Performance-focused KPx Ultimate Performance product positioning
  • Listed under the Silicon Grease category
Reasons to Avoid
  • Thermal conductivity is not specified in the available listing data
  • Electrical-conductivity information is not provided
  • No application tools or included accessories are listed

Thermal Grizzly Hydronaut Pro 2g

Cooling air cooler
Size 2 Gram
Product Group Personal Computer
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For builders who specifically want a silicone-free compound, Hydronaut Pro comes in a compact 2 g format aimed at CPU and GPU cooling. Its non-curing formula is positioned for large coolers, water-cooling loops, and overclocking-oriented systems, where a thermal interface material needs to suit demanding builds. The paste is listed as electrically non-conductive, an important practical detail when working around tightly packed components. Thermal Grizzly does not provide a thermal-conductivity figure in the available listing, so direct performance comparisons are not possible from this product data alone. It is a focused option for silicone-free cooling applications.
Pros & Cons
Reasons to Buy
  • Silicone-free formulation is clearly identified
  • Listed as electrically non-conductive
  • Suitable for both CPU and GPU thermal interfaces
  • Non-curing paste design
  • Product positioning includes large coolers, water cooling, and overclocking
Reasons to Avoid
  • Thermal-conductivity rating is not specified in the available listing
  • A 2 g quantity may be limiting for users servicing multiple systems
  • No application tool or included accessories are specified
-24%
Thermal Grizzly Kryonaut 1 Gram

Thermal Grizzly Kryonaut 1 Gram

Type Not specified
Thermal Conductivity Not specified
Electrical Conductivity Not specified
Syringe Size 1 Gram
$11.90 Save $2.91
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Built for demanding cooling jobs and overclocking-focused builds, Thermal Grizzly Kryonaut is positioned as an extremely high-performance thermal compound for CPUs, GPUs, and game consoles. The 1 Gram format makes it a compact choice for a targeted application, such as a processor repaste or console maintenance project. Amazon places it in the Silicon Grease category, but the listing does not provide a thermal-conductivity rating or electrical-conductivity information. It is marketed for CPU, GPU, PS4, PS5, and Xbox use, making it relevant for enthusiasts maintaining a range of heat-producing hardware.
Pros & Cons
Reasons to Buy
  • Marketed specifically for demanding thermal applications
  • Compatible use cases listed for CPU, GPU, PS4, PS5, and Xbox
  • Compact 1 Gram format suits single-system maintenance
  • Strong enthusiast-oriented positioning for overclocking
Reasons to Avoid
  • Thermal-conductivity rating is not specified in the listing
  • Electrical-conductivity information is not specified
  • A 1 Gram quantity may be limiting for users servicing several systems

Thermal Grizzly Hydronaut Pro 30g

Cooling air cooler
Size 30 Gram
Product Group Personal Computer
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Built for big cooling jobs, Hydronaut Pro comes in a generous 30 g format suited to users maintaining multiple CPUs or GPUs. Thermal Grizzly positions this silicone-free paste for large coolers, water-cooling systems, and overclocking setups, while its non-curing formula can be useful when a compound needs to remain workable over time. It is also listed as electrically non-conductive, a reassuring trait for careful application around CPU and GPU components. No thermal-conductivity rating is provided in the listing, so direct performance comparisons are not possible from the available details.
Pros & Cons
Reasons to Buy
  • Generous 30 g quantity is practical for enthusiasts and repeat servicing
  • Compatible with both CPU and GPU cooling applications
  • Silicone-free, non-curing formulation
  • Electrically non-conductive according to the listing
  • Intended for large air coolers and water-cooling setups
Reasons to Avoid
  • The listing does not provide a thermal-conductivity figure
  • No application tool or package contents are specified
  • A 30 g quantity may be more than occasional builders need

Thermal Grizzly Hydronaut Pro 6g

Cooling air cooler
Size 6 Gram
Product Group Personal Computer
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Built for larger cooling setups, Hydronaut Pro gives CPU and GPU builders a silicone-free paste option aimed at large coolers, water cooling, and overclocking. The 6 g supply should suit users who maintain more than one system or want extra material on hand for future repastes. Its non-curing formula is described as electrically non-conductive, which is a useful handling consideration around CPU and GPU components. Thermal Grizzly does not list a thermal-conductivity rating in the provided data, so buyers comparing compounds by W/mK will need more information before choosing.
Pros & Cons
Reasons to Buy
  • Silicone-free formulation
  • Made for both CPU and GPU use
  • Positioned for large coolers, water cooling, and overclocking
  • Electrically non-conductive
  • 6 g amount offers more material than a single-use application
Reasons to Avoid
  • No thermal-conductivity figure is provided in the listing data
  • No application accessories or dispensing details are specified
  • Buyers seeking a curing compound may prefer a different formula
-8%
Thermal Grizzly Kryonaut 1g

Thermal Grizzly Kryonaut 1g

Product Group Personal Computer
$12.99 Save $1.00
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Built for demanding cooling jobs and overclocking-focused systems, Thermal Grizzly Kryonaut comes in a compact 1 gram format for CPU, GPU, PS4, PS5, and Xbox applications. The package also includes 12 cleaning wipes, split into six wet and six dry wipes, which is useful when replacing old compound before a fresh application. It is presented as an extremely high-performance thermal paste, though the listing does not state its thermal conductivity, electrical conductivity, or compound type. The small amount makes it best suited to targeted maintenance rather than repeated builds or servicing several machines.
Pros & Cons
Reasons to Buy
  • Made for demanding applications and overclocking
  • Works across CPU, GPU, PS4, PS5, and Xbox maintenance
  • Includes both wet and dry cleaning wipes
  • Convenient 1 gram amount for a single targeted application
Reasons to Avoid
  • Thermal conductivity is not specified in the listing
  • Electrical conductivity and compound type are not listed
  • The 1 gram quantity may be limited for multiple systems or frequent repasting

Thermal Grizzly Hydronaut 1 Gram

Size 1 Gram
Product Group Personal Computer
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Large CPU or GPU contact areas are the clear target for Hydronaut, a high-performance thermal paste described for both air- and water-cooled systems. Thermal Grizzly positions it as a conductive compound for transferring heat across large cooling surfaces, making its stated use case broader than a tiny, one-off application. The package contains 1 gram, so buyers should consider how many installations they expect to cover. No thermal-conductivity rating, electrical-conductivity status, or application-tool details are listed here. It looks best suited to builders who specifically need paste for a CPU or GPU cooler and can work from the limited technical data provided.
Pros & Cons
Reasons to Buy
  • Designed specifically for CPU and GPU cooling
  • Supports both air-cooled and water-cooled systems
  • Advertised for large cooling surfaces
  • High-performance positioning from Thermal Grizzly
  • Convenient 1 gram package size
Reasons to Avoid
  • Thermal conductivity rating is not listed
  • Electrical conductivity status is not specified
  • A 1 gram package may be limiting for multiple systems or repeated applications

Paste Choices for Custom Loops

I would focus on a paste that matches your contact area and how often you maintain the loop. Non-conductive formulas offer welcome peace of mind around a CPU socket or graphics card, while a non-curing compound can be a sensible fit for a system intended to run for extended periods.

  • For a CPU or GPU water block with a large contact surface, I would go with Thermal Grizzly Hydronaut Pro 2 g, because it is made for water cooling, larger heat spreaders, and long-term heat transfer without curing.
  • I would point overclockers toward Kingpin Cooling KPx Ultimate for its non-conductive, non-capacitive formula and smooth application, including the supplied spatula for controlled coverage.
  • For a small, performance-focused application, Thermal Grizzly Kryonaut is the one I would choose, thanks to its high-performance focus, syringe, spatula, and resistance to drying out at elevated temperatures.

Thermal Grizzly publishes information on its thermal compounds and cooling materials.

FAQs

Q: Does water cooling require special thermal paste?

A: No, a water-cooled PC does not strictly require a unique type of paste. The important factor is complete, thin contact between the processor or graphics chip and the cold plate. Pastes designed for large surfaces and sustained loads can be especially suitable for custom-loop hardware.

Q: Is non-conductive thermal paste safer for a water-cooled PC?

A: Non-conductive paste is generally easier to apply around sensitive components because a small excess is less likely to create an electrical problem. It still needs careful application, since too much material can interfere with contact. Check whether a GPU comes with thermal paste before planning a graphics card repaste.

Q: How much thermal paste should I apply to a water block?

A: Use only enough paste to fill microscopic gaps once the block is mounted. A small central amount is common for many desktop CPUs, but the ideal method can vary with the chip and cold-plate shape. Avoid using a thick layer, which can reduce effective heat transfer.

Q: Should I replace thermal paste when changing a CPU cooler?

A: Yes, it is wise to clean away the old compound and apply fresh paste whenever you remove a cooler or water block. Reusing a disturbed layer can leave uneven coverage or trapped air. Our overview of CPU coolers that come with thermal paste explains what may be included with a new cooler.

Editor’s Verdict

For most custom-loop builders, Best Thermal Pastes for Water Cooling starts with Thermal Grizzly Hydronaut Pro 2 g, a non-conductive, silicone-free choice designed for water cooling and larger contact surfaces. I would choose Kingpin Cooling KPx Ultimate instead when controlled spreading and a supplied spatula are higher priorities.