Does thermal paste expire?

Does thermal paste go bad? Believe it or not, much like medicine and food, thermal paste also has a shelf life and can go bad. Generally, manufacturers give their thermal paste a lifespan of 3 to 5 years. That’s if it sits under optimal conditions, which may not be the case for you.

How to check if your thermal paste expired

close-up Thermal compound on CPU

Has my thermal paste expired? Well, the dreaded answer is… it depends!

Different manufacturers use different compound mixtures and syringes. There are many brands, including ARCTIC, Noctua, Thermal Grizzly, Arctic Silver, Coolaboratory, Cooler Master, and Corsair, to name a few. So it’s hard to give a single answer.

If your thermal paste hasn’t been used since the last time you applied it to your CPU and was placed in a relatively normal temperature area with a tight seal, then it should still be good. Emphasis on should.

We recommend putting some on a metallic surface and spreading to check its consistency and smoothness. If it has separated, comes out clumpy or watery, then throw it away and get yourself a new tube of thermal paste. You don’t want this near your CPU and heat sink, as a thermal paste’s consistency is crucial to regulating heat dissipation.

In the worst-case scenario, you’re looking at very bad overheating that can fry your CPU and motherboard.

How to properly store thermal paste

If you’ve got a relatively new tube of thermal paste and are worried about when it’s going to expire, then you can prolong its life span by doing the following things:

  • Twist the cap back on to the thermal paste syringe tight enough. If this isn’t possible because of how the syringe is made then putting it in a Ziploc bag is the next best thing.
  • Don’t pull the plunger back. This the part you push with your thumb to get the thermal paste to come out. If you do then you will introduce air into the barrel and expose the remaining paste to oxidation.
  • Find an area with a normal room temperature. Nothing overly hot or cold and without being too humid. Avoid an attic or basement as these can get incredibly hot or cold depending on the season.
  • Cover the tube or place it in a box to avoid exposure to sunlight. A shelf drawer is likewise sufficient.

How often to replace thermal paste

There are a couple of scenarios when you should replace the thermal paste on your CPU and heat sink.

Every time you remove the heat sink from your CPU, you should replace the thermal paste. If you don’t do so, you will introduce air pockets when putting it back on because of how the paste was separated. This causes trouble when dissipating heat and can damage your CPU.

So if, for example, you’re taking your heat sink off for a nice thorough cleaning of dust inside your PC, then do yourself a favor. Wipe the CPU and heat sink clean with isopropyl alcohol using a cotton swab or pad. Reapply some thermal paste, and you’re set.

Some people go a step further and recommend replacing the thermal paste on your CPU every two to three years, regardless of whether you touch the heat sink. Most seem to agree that doing it every year is a bit excessive.

If you have a prebuilt PC, then we and others recommend replacing the thermal paste that came with it, no matter how old the PC is. This is one of the easiest and cheapest ways to get more performance out of your PC. Typically PC manufacturers cut corners to maximize profit through some means. Be it through a cheaper case, lower quality thermal paste, or something else.

Does it make a difference?

Several people have tested their CPU temps with old paste and newly applied paste. What’s the result? Polarizing. For some, it’s lackluster, while others see big improvements in temperature reduction.

This big disparity in results may be due to poor quality paste aging badly and showing a much greater improvement when replaced.

If you’re a tech and gaming enthusiast and like having your computer run like a finely tuned car that squeezes every performance advantage, it can then more power to you. Your thermal paste would likely sit unused otherwise, so it’s good to get the most out of what you own.

Too much thermal paste is bad

Poorly applied and excessive thermal paste has become a meme. The purpose of thermal paste is to help with the conductivity of the CPU and heatsink. However, there is a point where thermal paste will become an insulator if you put too much.

If you’re a novice, you might think you’re doing more good by applying more paste, but this isn’t the case. Too much will affect temperature regulation and, in some cases, overheat the CPU and do damage.

What happens if you don’t use thermal paste?

Again conductivity will suffer, and as a result, so will the CPU’s ability to displace heat. The CPU will operate at temperatures higher than necessary. If you’re stressing your CPU or overclocking, this will lead to throttling or possible damage. Given the low cost of a syringe, there is no scenario where not applying it makes sense.

If it turns out that your thermal paste has indeed expired, then get yourself a new one. Even the most expensive ones are reasonable when you factor in the results in reducing CPU temp you might get! 

Through our years of experience working and building our PC builds, we had the opportunity to test different pastes. The one we continuously come back to and recommend is the Arctic MX-4.