1. What is thermal paste and what does it do ?
Thermal paste is a conductive substance made of metal oxides and/or other materials. It’s primary function is to fill air gaps between the heat-generating component (CPU, GPU) and the heat-transferring component (heatsink). By filling this air gap with a thermally conductive material, thermal paste helps to remove the physical barrier that exists between these components. This is important because it means heat can more effectively permeate through the interface to be transferred away by the heatsink.
2. How to apply thermal paste
Firstly, the heatsink must be clean. Thermal paste will not bond to a surface that is dirty or dusty – this is why good airflow inside your PC is important! I recommend using some compressed air (the canned air you use for cleaning dust off electronics works well) to blow out any debris on both the heatsink and the heat-generating component. Do not touch the heatsink or CPU/GPU with your bare hands inside your motherboard. Almost all thermal pastes are electrically non-conductive, but when in doubt – use gloves! Thermal paste is packaged in syringes for a reason. A small amount of paste applied accurately will go further than too much paste applied poorly. These pastes are quite thick and difficult to spread, so I also recommend using the “pea” method when applying thermal paste – simply place a small blob of paste onto the center of your heatsink in the shape of a pea. Now you’re ready to put everything back together!
Most thermal pastes will come with some kind of installation guidelines on the package, but the process is always virtually identical – place a small amount on the center of the heatsink and spread it evenly around using your finger or a clean plastic bag. Inflating/blowing up a plastic bag will help prevent contamination from particles on your hand or from spreading paste too thin.
3. How long does thermal paste last ?
Before I go into the expiration time of thermal paste, it’s important to realize that even though pastes can dry out or harden over time – this does not mean they are no longer useful. Depending on the composition of your paste, after time has passed you may notice a decrease in heat transfer performance. However, once the air gap between your CPU/GPU and heatsink has been filled, it will not matter if your paste is old or new – the thermal performance difference between fresh paste and old/hardened paste is negligible.
4. Does CPU thermal paste expire?
CPU thermal pastes don’t typically expire. The packaging will often state that the paste can be used for 2-3 years after opening, but if your paste is kept in a cool and dry environment there’s no reason you couldn’t use it much longer than this.
Does GPU thermal paste expire?
GPU pastes are very similar to CPU pastes in this regard. The packaging will typically state that the paste can be used for 2-3 years after opening, but if your paste is kept in a cool and dry environment there’s no reason you couldn’t use it much longer than this.
5. How to tell if your thermal paste has expired?
If your paste has dried out or hardened over time, this will make it more difficult to spread onto the surface of your heatsink. However, whether you notice this happening is another thing entirely. Thermal paste is usually transparent, so if you can’t see any change in color – it doesn’t necessarily mean that there has been no negative change in performance. The best way to tell if your paste has expired is by the performance! Disclaimer: If your paste is contaminated in any way, it will affect its performance.
6. What to do if your thermal paste has expired?
If your thermal paste has dried out and doesn’t spread as easily, it is time to replace it. However, if you can still see that the paste is “fresh” and hasn’t thickened much over long periods of time – it’s safe to assume that its performance will remain relatively unchanged. If this is the case, simply wipe the majority of your existing paste off and replace it with a small amount of fresh paste for future use. I would definitely recommend removing as much old paste as possible though since this will help to maximize heat transfer from your CPU/GPU to your heatsink.