Short answer: use one pea-sized dot in the centre of a desktop CPU and let the cooler spread it. By weight that is roughly 0.2 g. Noctua rates its 3.5 g NT-H2 tube at about 15 applications on a medium-sized CPU, which works out to about 0.23 g each. Big chips like Threadripper need far more, and a GPU die needs a thin layer that covers the whole die.
| Chip | How much paste | How to apply |
|---|---|---|
| Small CPU (laptop, mini PC, older desktop) | about 0.18 g (Noctua: ~20 uses per 3.5 g) | small dot in the centre |
| Mainstream desktop CPU (AM5, LGA1700, LGA1851) | about 0.23 g (~15 uses per 3.5 g) | one pea-sized dot in the centre |
| Large CPU (Threadripper, Xeon, EPYC) | about 1.2 g (~3 uses per 3.5 g) | thin X or several small dots |
| GPU die | enough to cover the bare die thinly | thin X or a thin even spread |
| Liquid metal | a very thin film, on the die only | the brush that comes with it |
Getting it wrong in either direction causes problems. Too little paste leaves bare gaps between the CPU and cooler, the exact air pockets paste exists to eliminate. Too much doesn't help conductivity and can squeeze out past the edges, risking contact with the socket or surrounding components.
How much to actually use
For a standard desktop CPU, a pea-sized dot in the center of the integrated heat spreader is the standard amount for most carbon-based and metal-oxide pastes. The cooler's mounting pressure spreads it evenly across the surface when you install it, you don't need to spread it yourself with a card or brush for most consumer coolers.
For larger dies, like Threadripper or server CPUs, or for GPUs with a wide contact surface, a thin X-pattern or a few smaller dots spread across the surface gives more even coverage than a single central dot.
Liquid metal is the exception. It requires a much thinner layer, applied with the included brush or applicator, precisely on the die surface and nowhere else, since any overflow carries a short-circuit risk. If you're using a liquid metal compound like Thermal Grizzly Conductonaut, follow the manufacturer's specific application instructions rather than the pea-sized-dot rule.
How much thermal paste on a GPU
A graphics card die has no metal heat spreader, so the paste sits directly on the silicon and has to cover all of it. A single central dot often leaves the corners dry on a large die. Use a thin X from corner to corner, or spread a thin, even layer across the whole die with a card, then remount the cooler with even pressure.
Most GPU repaste problems come from the thermal pads, not the paste. The pads on the memory chips and power stages have set thicknesses, and replacing them with the wrong thickness can stop the cooler touching the die properly. Measure the old pads before you order new ones.
How many grams of thermal paste per CPU
Manufacturers rarely state grams per application, but tube ratings give a good guide. Noctua lists its 3.5 g NT-H2 at about 20 applications on small CPUs, 15 on medium CPUs and 3 on large ones. That puts a normal desktop application at around 0.2 g, so a 4 g tube like the Arctic MX-4 covers many rebuilds.
Removing old paste before reapplying
Before applying new paste, whether you're upgrading coolers or doing routine maintenance, remove the old paste completely:
- Power down and unplug the system, then remove the cooler.
- Wipe the CPU's heat spreader and the cooler's contact plate with isopropyl alcohol (90%+ concentration) and a lint-free cloth or coffee filter.
- Repeat until no residue remains and the surface is fully clean and dry.
- Apply fresh paste before remounting the cooler.
Dried, cracked, or pumped-out paste is a common cause of temperature creep in systems that have run for years without maintenance, and it's a five-minute fix once you have isopropyl alcohol and a clean cloth on hand.
When to reapply
Most carbon-based and metal-oxide pastes are rated for multiple years of stable performance, some, like Arctic MX-6, specifically advertise 8+ years without drying out. You generally don't need to reapply on a schedule. Reapply when:
- You're removing the cooler for any reason (upgrade, cleaning, reseating).
- Idle or load temperatures have crept up noticeably compared to when the system was new, with no other explanation like dust buildup.
- The paste is visibly dried, cracked, or has migrated away from the die when you check it.
Phase-change pads like Honeywell PTM7950 are a different case entirely, they're designed for repeated thermal cycles without needing reapplication at all, which is part of why they've become popular for laptops and thin systems where opening the case repeatedly isn't practical.
Browse specific paste options with their rated conductivity and package sizes on the Consumercarts thermal paste comparison.
Compare popular thermal pastes
See how common picks stack up side by side: Arctic MX-4 vs Corsair TM30, Arctic MX-7 vs Noctua NT-H1 and Arctic MX-7 vs Thermal Grizzly Conductonaut, or browse every paste, pad and liquid metal in our thermal paste comparison.