If you’re building a computer, you need thermal paste to ensure that your computer’s central processing unit (CPU) doesn’t overheat. The paste is a conductive material that’s applied to your CPU to ensure close-as-possible contact between the hot CPU and the cooler. Existing computers also may need new thermal paste applied as it tends to dry out over years of use. Whether you’re installing thermal paste on a new build or an older machine that will first require cleaning off the previous paste, we’ll show you how to apply thermal paste properly.

Want the full rundown for installing your CPU? Check out our guide on how to install an Intel processor.

What is thermal paste?

Thermal paste is a thermally conductive compound that helps to transfer heat; it eliminates air gaps that would generally be present between two surfaces to facilitate a better transfer. In computer building, we place a bit of thermal paste between the CPU and the CPU cooler to ensure that heat is removed from the processor as effectively as possible. Without the addition of thermal paste, your CPU would overheat and could be damaged. If you haven’t already purchased thermal paste for your machine, be sure to check out our guide on the best thermal pastes.

How to clean off thermal paste

If you already have a working machine that needs thermal paste to be reapplied, you’ll first need to clean off the old thermal paste. Before beginning, ensure that the CPU cooler has been removed, and you can visually see the thermal paste; it is generally white or gray. If you are installing thermal paste on a new machine and don’t need to remove old paste first, skip to the next section — otherwise, continue below for more instructions.

What you will need:

• A microfiber cloth (not paper towls, as they can scratch the surface)
  • Rubbing alcohol (at least 90%)
  • Cotton swabs
  • A plastic spudger (optional)

Step 1: Begin by wiping the top of your CPU with the microfiber cloth to remove as much thermal paste as you can without issue.

Step 2: Dip the end of a cotton swab into the rubbing alcohol, then use it to wipe the top of your CPU gently; this will help to break up any hardened thermal paste. Optionally, use a plastic spudger to help remove any stubborn paste.

Step 3: Again, use a clean portion of the microfiber cloth or paper towel to remove any remaining thermal paste; the alcohol will evaporate almost immediately on its own.

Step 4: Repeat the above process to remove any old thermal paste that may be stuck to the underside of your CPU cooler.

How to apply thermal paste

Once you have both a clean CPU and CPU cooler (or you just took them brand-new out of the box), we can begin applying thermal paste. The key to applying thermal paste is not to overdo it; you only need to use a tiny pea-sized bit of paste — anything more would be excessive. Double-check to ensure you have all the required equipment below, then begin the process.

What you’ll need:

• A clean CPU installed in your motherboard socket
  • A clean CPU cooler ready to install
  • CPU thermal paste
  • A microfiber cloth (or paper towel)

Step 1: With your CPU already installed into your motherboard, place a small pea-sized drop of thermal paste on the CPU’s center.

Step 2: Next, install the CPU cooler while applying top-down pressure to the unit. Note that there is no need to first spread the paste before installing the cooler; the cooler’s pressure will evenly distribute the thermal paste.

Step 3: Once the cooler is installed, check the CPU’s edges to see if any excess thermal paste has spilled over, and, if needed, wipe it away with a microfiber cloth or paper towel.

Does thermal paste need to be reapplied regularly?

After finishing this process, one question that you might have is how often, if ever, does the CPU thermal paste need to be replaced? One of the largest chip manufacturers in the world, Intel, recommends reapplying the solution “every few years” or if you “remove your cooler for any reason.” Typically, your thermal paste will last you quite a while, but keep an eye on your temperatures, as if they spike, it could be a sign your thermal paste is drying up.