Thermal Paste and Repasting Guide
Paste choice matters far less than application and mounting pressure. Most repasting fixes a mounting problem, not a paste problem.
The short answer
Thermal paste choice produces small temperature differences between reputable products, while application quality and mounting pressure produce large ones. Repasting is worthwhile every few years or when temperatures rise noticeably, since paste dries out gradually rather than failing suddenly. Applying too much paste is less harmful than applying too little, as insufficient coverage leaves air gaps that insulate rather than conduct.
Verified and last updated August 12, 2026.
- Time needed
- 12 min
- Difficulty
- Intermediate
- Read time
- 3 min
Thermal paste attracts more debate than its impact justifies. The difference between reputable products is a couple of degrees.
The difference between a good and a bad application is considerably larger, and mounting pressure is larger still.
Check dust first
Most temperature increases over time are dust in the cooler fins, not dried paste. Cleaning takes ten minutes and frequently resolves what people assume needs repasting.
Step 1: Establish whether paste is actually the problem
Temperatures rising over months has several causes and paste is not the most common.
Clean the cooler and filters first. If temperatures return to normal, you have saved yourself a job.
Step 2: Clean and apply correctly
Remove the old paste 10 minutes
Remove the cooler, then clean both the processor heat spreader and the cooler contact plate with isopropyl alcohol, ninety percent or higher, and a lint-free cloth. Remove all of the old paste; residue creates uneven contact. Let both surfaces dry completely before applying new paste.
Apply and mount 10 minutes
Apply roughly a pea-sized amount in the centre of the heat spreader for a typical processor. Mount the cooler and tighten the screws in a diagonal cross pattern, a little at a time, so pressure is even. Even mounting pressure matters more than the paste itself, and tightening one side fully before the other produces uneven contact.
That diagonal tightening pattern is the detail people skip. Uneven pressure means part of the die makes poor contact regardless of what paste is between them.
How much paste
Too little is worse than too much.
Insufficient coverage leaves air gaps, and air is an excellent insulator. Slightly excess paste simply squeezes out and does nothing harmful on a standard heat spreader.
A pea-sized amount in the centre suits most processors. Larger rectangular heat spreaders benefit from a line or a spread rather than a single dot.
Do not use so much that it runs off onto the socket, but do not be so conservative that coverage is incomplete.
Which paste to buy
Any reputable mid-range paste from a known brand. The differences are small.
Avoid liquid metal unless you specifically know why you want it. It performs better and it is electrically conductive, reacts with aluminium, and a spill can destroy hardware. The gain does not justify the risk for most people.
Avoid the paste included with very cheap coolers, which is genuinely poor. Coolers from reputable brands include acceptable paste.
Second-hand systems
Repasting a used system is almost always worthwhile, since you have no idea when it was last done or how well.
The second-hand hardware guide covers what else to check on a used machine, and the overheating guide covers diagnosing thermal problems that paste will not fix.
What works
What doesn't
Key takeaways
Frequently asked questions
How often should I replace thermal paste?
Every three to five years is a reasonable interval for most systems, though it depends on operating temperatures and paste quality. Paste dries out gradually rather than failing at a specific point. If temperatures have risen noticeably and cleaning dust has not helped, repasting is the next step.
Does expensive thermal paste make a difference?
A small one. The gap between reputable products is typically a couple of degrees, which is far less than the difference between a good and a poor application. Buying a mid-range paste from a known brand and applying it well beats buying the best paste and applying it badly.
How much paste should I use?
Enough to cover the heat spreader thinly when the cooler is mounted, which for most processors is roughly a pea-sized amount in the centre. Mounting pressure spreads it. Too little leaves air gaps that insulate, which is worse than slightly too much, so err toward more rather than less.
Should I spread it manually or let pressure do it?
Letting mounting pressure spread it works well for most processors and avoids introducing air bubbles. Manual spreading with a spatula is also fine and gives more control on large or rectangular heat spreaders. Both work; the important thing is complete coverage without trapped air.
About the author
PC Hardware & Performance Editor
Marcus has been building, breaking and repairing gaming PCs since 2011, first as a weekend favour for friends and then for eight years as a bench technician at an independent repair shop in Portland, where roughly a third of the job was diagnosing machines that "ran fine yesterday".
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