Repasting a Laptop

Clear the fin stack before you open anything. A packed heat exchanger produces the same symptoms as dried paste, and it is the more common fault by a wide margin.

If a repaste is genuinely needed, the pads and the screw sequence decide the result as much as the paste does — which is why a careless repaste can leave a laptop hotter than it was.

A note on this guide: this rests on how these assemblies are built and documented rather than on laptops stripped down here. See how we test.

The problem, as it appears

The fan is loud, the chassis is hot, and the machine slows down after a few minutes of anything demanding. It did not do this when it was new.

The internet's answer is that the thermal paste has dried out. Sometimes that is right.

Why going straight to paste disappoints

Because the most common blockage is somewhere you can reach without a screwdriver.

A laptop's heat exchanger is a stack of very fine fins, a few millimetres deep, sitting between the fan and the exhaust vent. It is the only exit heat has, and its geometry makes it an efficient filter for dust, hair and fibre. What accumulates is not a film on the surface — it is a mat pressed against the intake face of the stack, and it can close most of the aperture while looking like very little.

That produces exactly the pattern people diagnose as dried paste: fine at idle, rising fast under load, fan at full speed and nothing coming out of the vent. The difference is that this one is free to fix and carries no risk.

So the first job is to separate the two, and the way to do it is to measure before and after clearing the dust rather than to guess. Doing that honestly means knowing what the numbers mean, which is reading temperatures without misreading them.

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What actually matters

The assembly is shared, and the pads are part of it

This is the difference that catches desktop builders out.

A desktop cooler touches one thing. A laptop's heatpipe assembly commonly spans the CPU and the GPU together, and it also reaches over memory chips and power-delivery components that are covered by thermal pads rather than paste — because those parts sit at different heights and a pad bridges the gap that paste cannot.

Pads compress permanently. A pad that has spent four years under clamping pressure is thinner than it was, so refitting the assembly onto old pads leaves those components with a worse contact than before — while the CPU, with its fresh paste, reports an improvement. That is the mechanism behind a repaste that fixes the headline number and makes the machine less stable under sustained load.

Replacement pads must match the original thickness, which is a measurement rather than a preference. Too thin leaves an air gap; too thick holds the whole assembly off the CPU die, which is the one failure that is unmistakable and immediate.

Where each material belongs, and why they are not interchangeable, is set out in thermal paste vs thermal pads.

The screw sequence is an instruction, not decoration

The numbers stamped beside the screws are there because the plate is thin and spans several components.

Tightening one corner down fully before the others tilts the plate and lifts it off a die at the far end. The method is rounds — each screw a little, in the numbered order, repeated until all are seated — and the same order reversed on the way out.

This is the step most likely to produce a worse result than doing nothing at all, and it costs only patience.

Small dies want a small amount

Laptop CPU and GPU dies are bare silicon, small, and without the metal lid a desktop chip has.

A modest amount in the centre spreads under clamping pressure and covers what needs covering. Excess has nowhere useful to go: it runs off the edge of the die onto the substrate and the surrounding components, where it is at best a mess to clean.

Liquid metal is a different risk profile here

Worth being direct, because it is widely recommended and the reasons against it are specific rather than general caution.

It is electrically conductive, so any migration onto the board is a repair rather than a wipe. It reacts with aluminium, which appears in laptop heat spreaders and nearby hardware. And a laptop is carried, tipped and dropped in ways a desktop is not.

Manufacturers who ship it from the factory build containment around it. A retrofit inherits the risk without the design that manages it.

The fan may be the noise even when the paste is the heat

Two separate complaints often arrive together, and only one of them is a paste problem.

A bearing that has become audible will still be audible after a perfect repaste, because the noise is mechanical rather than thermal. Deciding which you actually have — before doing the work — is the argument in repasting vs replacing a noisy cooler.

Non-marring tools, because the case is the visible part

Laptop bases are held by clips as well as screws, and the clips release along an edge rather than at a point. A metal blade in that gap leaves marks on the one part of the machine you look at daily.

Screws also vary in length within a single base, and putting a long one into a short hole is a hole through something. Laying them out in the pattern they came from takes seconds.

The order to work in

1. Measure under a repeatable load, and write the number down.
2. Clear the fin stack from the exhaust side, holding the fan still.
3. Measure again. A large improvement means you are finished.
4. Check whether the remaining complaint is noise, which paste will not fix.
5. Check the service manual for your model, and the warranty position.
6. Repaste, replacing pads at their original thickness, in the numbered screw order.
7. Measure a third time, under the same load as step 1.

The mistake to avoid

Repasting a laptop whose problem was dust. The work carries real risk — clips, ribbon connectors, compressed pads, a thin plate over several dies — and if the fin stack was the fault, all of it was spent to fix something a blast of air would have solved. Measuring before and after clearing the dust takes ten minutes and decides whether the rest is worth doing.

The second mistake is reusing old thermal pads because they look intact. They are not intact; they are compressed, and the components under them are the ones that quietly limit sustained performance rather than the one on the temperature readout. A repaste that improves the CPU number and leaves the power stages worse is a repaste that made the machine feel faster for two minutes and less stable for an hour — which is also the wider point in when to replace thermal paste.