Do I Need To Remove Old Thermal Paste Before Applying New One?

Thermal paste, also known as thermal compound, helps improve the conduction of heat between the CPU/GPU and the cooler so that it can be dissipated and not cause overheating. 

However, when replacing a cooler, CPU, or GPU, most PC owners are not sure whether they should wipe off the previous thermal paste before applying the new one.

It is recommended to remove the old thermal paste before applying the new one. This is to avoid creating a poor seal or bubbles from forming between the CPU/GPU and the heatsink which reduces the cooler’s performance, causing overheating.

In addition, thermal paste should not be reused as it could be exposed to contaminants which could affect its performance. Always use fresh thermal paste after replacing or removing a heatsink or cooler. 

How To Reapply Thermal Paste (Step by Step)

The factory thermal compound that comes applied to your PC’s graphics card or CPU is not always of the best quality. Or a component may have stayed in a store for too long, causing the thermal paste to harden and lose its conductive properties.

Hardened or expired thermal paste can cause your CPU or GPU to overheat, thus limiting its performance (throttling). To avoid this problem, it is best to apply a new, better-quality thermal paste that will help the cooler or heatsink dissipate as much heat as possible from the processor and graphics card.

Reapplying the thermal paste is not difficult and you can do it yourself by following a few simple steps. You will need the following when applying thermal paste:

  • Microfiber paper towel
  • Cotton swabs
  • isopropyl alcohol
  • Thermal paste
  • Screwdriver

Step 1. Remove The Mounting Screws 

If you have a cooler or heatsink installed, you need to unscrew it and remove it to gain access to the top of the CPU as well as the underside of the cooler where the thermal paste is to be wiped off and reapplied. 

Depending on the design, you may be able to do this by hand, but in some cases, a screwdriver is needed to unscrew the cooler or heatsink from the motherboard.

2. Wipe Off The Old Thermal Paste Completely

Unless the CPU or GPU is brand new, you have to wipe off the previous thermal paste and other foreign material that may be on its surface.  

Isopropyl alcohol is recommended when cleaning the processor and graphics card because, unlike water, it does not conduct electricity and does a good job of getting rid of residual thermal compound.

Start by using a dry paper towel to wipe off as much of the old thermal paste as you can from both the cooler and CPU or GPU. 

Next, apply some isopropyl alcohol to the paper towel to remove any residual thermal paste. Use a cotton swab with a little bit of isopropyl alcohol to clean the sides of the processor or graphics cards where the paper towel is unable to reach.

Finish by wiping off both components with a dry paper towel and ensure that no fiber or any other foreign material is left on the surface where the new thermal paste is to be applied.

Step 3: Apply The New Thermal Paste

Take your thermal paste of choice and apply a small amount to your CPU or GPU, just a drop (about the size of a pea) in the middle is usually enough. Applying too much thermal paste could cause it to spill over to the sides when you place the cooler or heatsink back on. 

Some thermal paste brands contain metal particles and care should be taken to ensure that they do not come into contact with the motherboard because they could short-circuit it.

Step 4: Place Your Cooler or Heatsink Back On

Once you’ve applied the right amount of thermal paste, place the cooler or heatsink back onto the motherboard. Placing the cooler or heatsink back on and tightening the mounting screws will allow the thermal paste to be spread evenly between the CPU/GPU and the cooler, thus ensuring proper conduction and heat dissipation.

The following video explains the process of applying thermal paste in more detail:

The Effect of Old Thermal Paste On Overheating

Old thermal paste can definitely cause overheating in your computer because it tends to harden over time (after 2-3 years), thus reducing its thermal conductivity(effectiveness) and affecting performance. Also, if the old thermal paste was not initially sufficiently applied, it could result in overheating. 

Keep your computer cool by applying fresh thermal paste after removing the old one. When replacing old thermal paste with a new one, it is important to check that the fans are working properly, and clean the computer (especially if dust and other debris have built up in the enclosure), This will not only improve performance but internal air circulation as well.

Why You Shouldn’t Clean Thermal Paste With Wet Wipes

You should not clean thermal paste using wet wipes because they contain water that could short-circuit the motherboard and damage it. Instead, use a dry microfiber paper towel with a bit of isopropyl alcohol to clean off the old thermal paste.

Another reason why you should not use wet wipes to clean thermal paste is that some contain soap. This means you could leave soap residue on the surfaces, thus introducing contaminants that could affect thermal conductivity.

Also, unlike isopropyl alcohol, water does not dissolve thermal paste to allow it to be removed with ease.

Thermal Paste And Damage To The Motherboard

Unless the thermal paste you are applying is conductive, it will not damage the motherboard. But if you are using conductive thermal paste, such as liquid metal, apply it with a lot of care to ensure it doesn’t come into contact with the motherboard as it could short-circuit it.

Non-conductive thermal paste only causes damage to the motherboard board when it is wrongly applied and gets into areas where it shouldn’t, such as exposed CPU socket pins where it could cause poor connections by acting as an insulator.

To be on the safe side, apply just enough thermal paste so that it doesn’t spill to the edges of the processor or graphics card.

Deciding What Thermal Paste To Use

For the most part, it does not matter what thermal paste you use as long as it is from a reputable manufacturer. However, if you will be overclocking your CPU and want the best performance you should consider getting a more expensive thermal paste with better thermal conductivity or using liquid metal.

Most ordinary thermal pastes available in the market, such as MX-4, Arctic Silver 5, Thermal Grizzly, and Noctua NT-H1, differ in their performance by only a few degrees.

Keep in mind that thermal paste is only one part of the equation when it comes to preventing your PC from overheating, other factors such as ensuring fans are running at the proper speed as well as your choice of a cooler or heatsink also make a significant difference.

Using Toothpaste As Thermal Paste

Toothpaste should not be used as thermal paste because it doesn’t meet the high heat transfer rate required to dissipate heat and prevent overheating. Also, it contains water as one of its ingredients which means it will dry out fast when subjected to high temperatures.

You can get a tube of thermal compound for as low as $4-$5, in fact, some coolers come with their own thermal paste so you don’t have to purchase one. Since the CPU and GPU are some of the most expensive components in a PC build there is no need to risk damaging them just to save a few bucks.

Final Thoughts

Always remove the previous thermal compound before applying new, fresh thermal paste to avoid poor seals and bubbles that could affect the efficiency at which the thermal compound transfers heat.

When applying new thermal paste ensure that the surfaces are clean and you use just enough thermal paste so that it doesn’t spill to the sides and damage the motherboard. Thermal paste should be reapplied about once every 3 years since it hardens over time.

For ordinary computer users, just about any thermal paste will do, just ensure you get one from a credible company. High-end thermal compounds and liquid metal are for those who overclock their CPU and those who need the best performance possible on their machine, for instance, gamers.

Do not use toothpaste as a substitute for real thermal paste as it does not have the same conductive properties as true thermal compound and wouldn’t last long before hardening.

Eustace G.
Eustace G.
Eustace is a technology enthusiast and avid gamer who holds a Bachelor's Degree in Telecommunication and Information Engineering. His passion and knowledge of computers, and technology in general, is channeled towards helping others understand complex concepts, solve problems, and make informed decisions.


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