Thermal Paste, Realistically
The difference in real-world CPU temperatures between mid-tier paste and premium paste is typically 1-3°C under identical conditions. This is far smaller than the differences from mount pressure, cooler quality, case airflow, and ambient room temperature. Paste choice matters least in a system that already has all the other variables handled well.
Where paste choice matters more: heavily overclocked CPUs pushing thermal limits, laptops with limited cooling headroom, and GPUs where poor factory paste applications sometimes leave measurable performance on the table. For a stock desktop CPU with a competent cooler, paste choice is a small optimization within a larger cooling system.
What matters more than brand: application technique, correct amount (pea-sized dot in the center for most modern CPUs), even mounting pressure, and paste condition. Old dried-out paste from a the entry tier tube performs worse than fresh mid-tier paste. Store paste tightly capped and use it within 2 years of opening.
PTM Pads: The Newer Option
Phase-change thermal materials are thin sheets that stay solid at room temperature and transition to a liquid-like state at operating temperature. This gives you paste-like thermal conductivity without the pump-out problems that can affect paste over years of thermal cycling. Honeywell PTM7950 has become the most popular in the PC community because it delivers competitive thermal performance and dramatically longer service life.
PTM pads are especially compelling for laptops (where cooler pressure is fixed and paste pump-out is a real long-term issue), high-heat CPUs and GPUs (where paste degradation happens faster), and any setup where you want to install once and forget. The trade-off is that PTM pads require slightly more care during installation — the pad must be perfectly aligned with the CPU die and not creased or contaminated during handling.
For most desktop CPUs, PTM pads and quality paste perform equivalently after break-in. Pads shine over paste primarily in longevity, not peak performance. If you plan to keep the cooler mounted for 5+ years, PTM pads are worth the small extra effort during install.
Our Top Picks
Arctic MX-6 $
The default recommendation — competitive thermal performance with the top pastes at a fraction of the price, in a generous 4g or 8g tube.
- 4g and 8g tubes available
- Non-conductive, non-capacitive
- 8-year application life
- MX Cleaner included in some kits
Thermal Grizzly Kryonaut $$
The performance-oriented benchmark — measurably competitive with the best pastes on the market for anyone building a heavily-overclocked or thermally-constrained system.
- Single-syringe application
- Non-conductive
- Zinc oxide + carbon-based blend
- Reference for enthusiast builds
Honeywell PTM7950 Phase-Change Pad $
The PTM pad that made the technology mainstream in the PC space — install once, forget for years, with paste-equivalent thermal performance.
- Cut to fit any CPU or GPU
- Requires break-in cycle
- No pump-out over time
- Multiple die-cut sizes available
Noctua NT-H2 $
Noctua's paste — high-quality, well-tested, and easy to apply with the included cleanup wipes. The set-and-forget mainstream choice.
- 10g tube
- 3.5g starter tube option
- Includes cleaning wipes
- 5-year application life
Cooler Master MasterGel Maker $$
Nano-diamond enhanced paste with high thermal conductivity and a smooth application consistency — an easy-to-apply premium option.
- Diamond particle blend
- Smooth application
- Non-conductive
- Includes spreader tool
Thermal Grizzly Conductonaut (Liquid Metal) $$
Gallium liquid metal for delidded CPUs and heat-limited overclocking projects — highest thermal conductivity available, with serious handling requirements.
- Highest thermal conductivity
- 1g syringe
- Requires nickel-plated cold plate
- Electrically conductive
Quick Buying Guide
| Product | Best For | Longevity | Price Tier |
|---|---|---|---|
| Arctic MX-6 | Default paste for any build | 8 years | $ |
| Thermal Grizzly Kryonaut | Overclocked/enthusiast builds | 3-4 years | $$ |
| Honeywell PTM7950 | Install-once setups, laptops | 10+ years | $ |
| Noctua NT-H2 | Set-and-forget mainstream | 5 years | $ |
| MasterGel Maker | Premium, easy application | 5 years | $$ |
| Conductonaut Liquid Metal | Delidded / laptop repaste only | 2-3 years | $$ |
For most builds, Arctic MX-6 or Noctua NT-H2 delivers everything you need. Step up to Kryonaut for overclocking projects. Consider PTM7950 for any build you plan to keep untouched for years. Avoid liquid metal unless you have a specific reason — the temperature win rarely justifies the handling risk.
Application Technique in Detail
The pea method: place a single small drop of paste in the center of the CPU IHS, then mount the cooler evenly using a cross-pattern screw sequence. The cooler's mounting pressure spreads the paste outward from the center in a roughly circular pattern that covers the IHS completely by the time you have finished torquing the screws.
The line method: use a thin line of paste along the CPU die's long axis for rectangular-die CPUs like Threadripper. The cooler's pressure spreads the line perpendicular to the axis to cover the whole die area. Attempting the pea method on Threadripper-style dies often leaves the corners uncovered.
Manual spreading with a spatula is technically valid but easy to mess up. Air bubbles trapped in manually-spread paste create voids in the thermal joint that reduce heat transfer measurably. The pea and line methods use mounting pressure to evenly distribute paste without introducing air, which is why they are recommended over manual spreading for most builds.
Installing a PTM Pad Correctly
PTM pads require a slightly different install than paste. Cut the pad to fit the CPU IHS (leaving a small margin on all sides), peel one protective layer, place the pad on the CPU with the exposed side up, then peel the second layer just before mounting the cooler. The pad must not be creased, contaminated with dust, or misaligned — errors in installation are more consequential than with paste.
PTM pads require a break-in cycle. On first use, the pad is thicker than its final state. Run the CPU under load for 15-30 minutes to reach operating temperature; the pad phase-changes and thins to its final thickness. Peak thermal performance is achieved after several thermal cycles, so give it a day or two of normal use before comparing before/after temperatures.
One under-discussed factor: paste for GPU repastes. GPUs use dedicated die-to-heatsink thermal interfaces and often use thermal pads for VRM and VRAM components in addition to paste on the main die. When repasting a GPU, plan to also replace the thermal pads — they compress over time and lose contact quality. Third-party pad kits (Gelid, Thermalright, Innovation Cooling) provide the sizes needed for common GPU models and improve results dramatically compared to reusing old pads.
Storage matters more than most guides mention. Thermal paste in an unopened tube typically stays viable for 2-3 years. Once opened, capped tightly and stored cool, it stays viable for 12-18 months of typical use. Dried-out paste is the single most common cause of poor thermal performance from name-brand products — it performs worse than fresh mid-tier paste and is impossible to diagnose without a comparison.
Frequently Asked Questions
How often should I replace thermal paste?
Modern pastes last 3-8 years depending on quality and operating temperature. Repaste when temperatures gradually climb over years, when you have the cooler off for other reasons, or when the CPU is under a specific heat challenge like a workload change. Do not repaste on schedule for its own sake.
How much paste should I use?
A pea-sized dot in the center of modern square CPU IHS surfaces. For rectangular dies like Threadripper, use a thin line the length of the die's long axis. The cooler's mounting pressure spreads the paste evenly — you do not need to manually spread it, and manual spreading sometimes traps air bubbles.
Is liquid metal worth the risk?
For most builds, no. Liquid metal delivers 4-8°C better temperatures than quality paste, but it is electrically conductive (a spill kills motherboards), reacts with aluminum, and can migrate on some IHS surfaces over time. Reserve it for delidded CPUs, laptop repasting where paste is failing, or heat-limited overclocking projects where the last degree matters.
Do I need to clean off old paste before applying new?
Yes, completely. Use isopropyl alcohol (90%+ recommended) and a lint-free cloth or coffee filter. Old paste mixes poorly with new paste and can create voids in the thermal joint. Clean both the CPU IHS and the cooler cold plate to bare metal before reapplying.
What about the paste that comes pre-applied on stock coolers?
It is fine for the first install and gets you through several years of typical use. When you replace the cooler or when temperatures start rising after long service, clean it off and apply fresh paste. Pre-applied paste is not premium but it is adequately-performing.