Home » How to Change Thermal Paste on a CPU, and When You Need To

How to Change Thermal Paste on a CPU, and When You Need To

Thermal paste fills the tiny gaps between a processor and its cooler, so heat can move from one to the other. Over the years it can dry out. If your computer runs hot, or you have just taken the cooler off, new paste is a cheap job that many people do themselves. Here is how, and when to leave it to us.

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When does thermal paste need changing?

  • The processor runs hotter than it used to, with no new dust or program to explain it
  • You have removed the cooler for any reason, such as upgrading the processor or cleaning
  • The computer is several years old and has never been opened
  • The paste looks dry, cracked or crusty when the cooler is off

A good paste can last several years, so there is no need to do it every few months.

What you need

  • Thermal paste. Choose a non-conductive one, which is safer for beginners
  • Isopropyl alcohol of 90 percent or stronger, and lint-free wipes, to clean the old paste off
  • A screwdriver that fits your cooler, and a clear, well-lit space
  • About an hour the first time

How it works, step by step

  1. 1
    Switch off and unplug

    Turn the computer off, unplug it from the wall, and touch the metal case to discharge static before you start.

  2. 2
    Remove the cooler

    Unplug the fan cable and undo the screws or clips, a little at a time. If the cooler is stuck, twist it gently side to side. Do not pull hard, because on some sockets a stuck cooler can pull the processor out with it.

  3. 3
    Clean off the old paste

    Wipe the processor and the base of the cooler with the alcohol and a lint-free wipe until both are clean and shiny, and let them dry for a minute.

  4. 4
    Apply the new paste

    For most processors, a pea-sized dot in the centre is enough. Do not spread it with your finger. The cooler will spread it when it is pressed down. Too much is as bad as too little.

  5. 5
    Refit the cooler

    Lower it straight down, without sliding it, and tighten the screws a little at a time, in a cross pattern, so the pressure is even. Plug the fan cable back in.

  6. 6
    Check the temperatures

    Switch on, and use a free temperature program to check that the processor is not running hot when it is idle and when it is working.

Which isopropyl alcohol (IPA) should I use?

Isopropyl alcohol, also called IPA or isopropanol, is the usual way to clean old thermal paste off a processor and cooler. For the inside of a computer, choose 90 percent or stronger, and 99 percent if you can. Weaker 70 percent alcohol is 30 percent water, which dries slowly and is not ideal near circuit boards. Use it on a lint-free wipe or pad, switch the computer off and unplug it first, and let everything dry before you start the computer again. Our Arctic MX-4 and Arctic MX-6 thermal paste kits include isopropyl alcohol cleaning pads.

Things to avoid

  • Do not use liquid metal paste unless you know the risks, because it conducts electricity and can short out a board
  • Do not touch the processor pins or contacts
  • Do not use too much paste: more is not better
  • Do not use water, or household cleaners, to clean the processor

Prefer us to do it?

If you would rather not open your computer, we will do it for you at our shop in Worcester. See our PC cleaning and thermal paste service. A full clean and re-paste starts from £45, with the paste and cleaning pads included.

Frequently asked questions

Can I use the old paste again?

No. Clean it all off and use new paste every time you refit the cooler.

How much paste do I need?

A pea-sized dot is enough for most processors. A tube holds enough for several jobs.

Will new paste lower my temperatures?

It can, if the old paste had dried out or was badly applied. If dust or a weak cooler is the real cause, it will not, and a clean may help more.

Is it safe to do myself?

Yes, if you take your time and follow the steps. If you are not sure, or your computer is under warranty, ring us first.

See also: PC cleaning and re-paste service, computer repair in Worcester and build your own PC.

Request a repair, upgrade or new computer

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