When Should You Replace Thermal Paste?

Paste degrades over years, not months. A machine that has become hot in its second summer almost certainly has a dust problem, and repasting it will change very little — which is why this is the wrong first move despite being the most commonly suggested one.

A note on this guide: this rests on how thermal interface materials age and where mounting pressure matters, not on repastes done here. See how we test.

The problem, as it appears

Temperatures that are higher than they were, or higher than someone else reports for the same parts. Repasting is the standard advice, it is cheap, and it feels like maintenance that ought to help.

Sometimes it does. Far more often the machine has a felted heatsink and blocked intakes, and the paste is doing exactly what it did on day one.

Why repasting first disappoints

Because it addresses the least likely cause, at the cost of the most risk. Removing a cooler means handling the mounting hardware and, on some sockets, the processor itself — and a repaste on a clean paste layer changes temperatures by almost nothing.

There is also a diagnostic problem with doing it early. If you clean the machine and repaste in the same session and temperatures improve, you have learned nothing about which one worked. Cleaning first, measuring, and only then considering paste keeps the variables separate.

What actually matters

Age, in years. Modern pastes hold up for a long time. Under about three years, a repaste is unlikely to be the answer unless something else points at it.

Whether the cooler has been disturbed. Any time a cooler comes off, the paste layer is broken and must be replaced before it goes back. This is the most common legitimate reason to repaste — not degradation, but disassembly.

Mounting pressure and seating. A cooler that is uneven, or whose bracket was tightened inconsistently, produces temperatures far worse than any paste choice. Diagonal, incremental tightening is what gets this right.

Whether the symptom fits. Dried paste tends to produce a sharp rise under load with rapid temperature spikes, because the interface conducts poorly the moment heat output climbs. A gradual warming across months is airflow.

The options, and who each suits

A mid-range paste suits everyone doing this. The gap between a competent paste and a premium one is a couple of degrees; the gap between a well-seated cooler and a poorly seated one is much larger.

This page contains affiliate links. If you buy through them, Ugly Fixes may earn a commission at no extra cost to you. Products are selected independently.

For a named pick, ARCTIC MX-6 is worth pointing at for a reason that is really about the category: it is electrically insulating — ARCTIC publishes 1.8 x 10^12 ohm-cm and a 7.5 kV/mm breakdown voltage rather than an adjective — so an over-generous application that squeezes onto the board is a mess rather than a fault. That is the failure mode an inexperienced repaste actually has.

Isopropyl alcohol and a lint-free cloth suit removing the old layer, and are not optional. Old paste has to come off both surfaces completely; residue left behind is a worse interface than what you removed.

Brushes suit the cleaning that should happen at the same time, since the cooler is off and the fin stack is finally accessible. If you are opening the machine anyway, this is the part that will actually lower temperatures.

Doing nothing suits a machine under three years old that has never been cleaned. Clean it, measure, and revisit — cleaning a gaming PC without damaging it covers that.

The mistake to avoid

Using liquid metal without understanding what it is. It conducts electricity, so any that escapes onto the board is a short, and it attacks aluminium coolers. The few degrees it gains are not worth a dead motherboard for the vast majority of people, and it is sold alongside ordinary paste with very little to distinguish the risk.

The second mistake is applying too much on the assumption that more is safer. Excess squeezes out under mounting pressure and can reach the socket, and on some socket designs paste in the pin array is a genuinely difficult problem to clean. A modest amount in the centre, spread by the cooler's own pressure, is the method. Whether pads or paste is the right material for a given surface is covered in thermal paste vs thermal pads.