NOTE: This is an overview on how to install thermal paste and may be all the guidance you need if you're already fairly confident with PC hardware and just want a basic overview, or if you've already built a PC before and need a quick refresher. See our full DIY gaming PC manual for much more detailed instructions on thermal paste application and all the other steps required to build your first PC properly, safely and confidently without making mistakes.
Here you will learn how to apply thermal compound/paste to a CPU and CPU cooler/heatsink. Applying thermal paste can be a little confusing, as there are various ways to do it and you'll no doubt have quite a few questions and concerns as a beginner.
But first, why should you even apply thermal paste to your processor? Well, if you're installing a stock CPU cooler, as in the one that already comes with your CPU, then there will already be thermal paste pre-applied to the bottom of the cooler, and there's no need to apply your own as the quality is fairly decent if your cooler is from a trusted manufacturer (ie Intel or AMD).
But if you're installing an aftermarket CPU cooler, either because you're planning on overclocking your computer or if you simply want the most effective cooling possible for your rig, then you'll need to apply your own thermal compound/paste as chances are an aftermarket heatsink won't already have it pre-applied.
Although you could still buy and apply your own paste to a stock cooler if you really wanted to, so you can use the very highest quality paste that you can to crank out that little extra more cooling performance, but it's not necessary. Just remember to properly remove the original paste first before applying your new paste of course.
So what thermal compound actually do? By applying thermal compound to your CPU and/or your heatsink, you can help maximize the effectiveness of cooling, and help keep temps down to prevent your system from overheating and risking your computer hardware getting damaged. It is easy to apply thermal compound and in certain situations it can make a significant difference, especially if you're overclocking.
Is it required or optional to have thermal paste on a CPU?
It's absolutely necessary, but as mentioned above it'll already be pre-applied to a stock CPU cooler. You only need to apply it yourself if you're assembling an aftermarket CPU cooler, or if you want to remove the stock paste and use your own higher quality one.
Do I Apply Thermal Compound to CPU or the Cooler/Heatsink?
You can apply the paste to either, although in most cases it's easier to just apply it to the top of your CPU before then installing the cooler onto the top of the CPU.
How do I apply thermal compound to a CPU?
Now let's get to the basic steps of actually applying thermal compound. Squeeze a tiny drop of the paste onto the top of your installed CPU in the center. You will only need about 2mm of the stuff (roughly the size of a grain of rice) and make sure you don't spill any of the paste on other parts of your system.
Now you'll need to spread the paste evenly across the CPU, although note that this only applies to square-based CPU coolers; if you have a circular cooler instead you don't need to spread it out as the pressure of the cooler will naturally spread it out.
So, if you have a square-based cooler, use an object with a straight edge such as a razor blade or a credit card, and spread the thermal compound evenly on your CPU. Make sure that the object you use is clean to start with before you start spreading the paste around. The paste should end up as a thin layer across the CPU surface without any gaps.
When you think that you have applied the paste properly, you can then proceed to install your heatsink onto your CPU core. That's practically it for applying thermal compound/paste. For full detail and photos, including everything else you need to know about installing your cooler and other parts, see our full PC building book.