Thermal paste — how much and how

1. Step 1 of 2

   How much paste

   A pea-sized dot in the centre of the CPU lid. On large CPUs with a rectangular lid, such as Threadripper, spread a thin layer across the whole surface instead.

   Independent testing has repeatedly shown that the differences between application methods — dot, cross, five dots, spreading — fall within one to two degrees. That is less than the variation between two samples of the same cooler.

   Too little paste is markedly worse than too much. Excess is squeezed out at the edges, whereas a shortfall leaves areas with no thermal contact at all.

2. Step 2 of 2

   When to replace it

   Paste does not need replacing on a schedule. Replace it when you remove the cooler, or when temperatures rise with no other explanation.

   Removing and refitting a cooler always requires fresh paste. Once a layer has been compressed it will not re-form even contact.

   Clean with isopropyl alcohol and a lint-free cloth. Avoid paper towels — they leave fibres on the contact surface.

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