What is thermal paste?
It has many names but one main purpose
Thermal paste is a type of Thermal Interface Material (TIM). Thermal paste (Putty/Grease/Compound) is the primary type of TIM used when it comes to PCs, although sometimes thermal pads are also used. The job of thermal paste is to transfer heat from one component to another. Most of the time, you will see it used on the CPU or GPU to transfer the heat from the chip to the heatsink, so it can then be expelled out of your system.
Keeping your PC components as cool as possible is very important, especially at higher workloads. If your CPU or GPU gets too hot, you may encounter thermal throttling, which will reduce performance. Prolonged use at higher temperatures can also reduce the longevity of your CPU and GPU. The goal is to keep things as cool as possible, which is why sometimes your PC fans will also get a bit louder as they are spinning faster to try and dissipate the heat.
What it’s used for
Keeping your PC components operating efficiently
As mentioned, it is used to help reduce the heat of some components inside your PC. Thermal paste is a high-conductivity material, and it fills in any gaps between your CPU/GPU chip and the heatsink. The goal is to eliminate any air bubbles or pockets to allow for a better heat transfer. While the heatsink is always quite firmly attached to both the CPU and GPU, there are still slight gaps between them which need to be filled (with paste) so the heat can transfer from the chip to the heatsink as much as possible.
Many companies pre-apply thermal paste to their cooling products. If you’ve ever bought a new CPU from either AMD or Intel, and it came with a heatsink, it likely already had the thermal paste applied. Same thing if you’ve ever bought a new air cooler or AIO, it likely had pre-applied thermal paste, or it came with a tube of some you can use between the components.
A lot of seasoned builders will have their own preference as to which thermal paste is best. However, the differences in temperatures are negligible across the board, and it almost doesn’t matter which thermal paste you choose if you are just going for a basic one. As long as you go with a well known manufacturer, you will be just fine in most cases.
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How to apply thermal paste to a CPU
Applying thermal paste to the CPU is a crucial step, but it’s a fairly simple task.
Different types of thermal pastes
Not all pastes are created equal
There are a few different kinds, and they all have slightly different properties though they aim for the same end result. Some of them have better heat conduction than others, while others are electrically conductive. Most of the more mainstream pastes are not electrically conductive, but if they are, you need to be extra careful when applying them as they could potentially make your CPU or GPU short out and no longer work at all.
Liquid metal and metal-based thermal pastes are some of the best performing options, but they have significant downsides. Metal-based pastes contain electrically conductive metals, so if they spill over to the circuit it could fry something, so these need to be used with great caution. Furthermore, liquid-metal cannot be used with aluminium heatsinks as it contains gallium. It is also liquid, so it is much harder to apply than your standard pastes.
Ceramic-based thermal pastes are not electrically conductive, so they are easier to use. They are also cheaper and easier to apply than some of the other types, making them one of the preferred pastes for novice and pro PC builders alike. However, they don’t have the best thermal conductivity, so you will see higher temperatures on your CPU/GPU than if you use a liquid-metal paste.
Silicon-based pastes are similar to ceramic-based pastes in the fact that they are good all around. They do offer better thermal conductivity than ceramic pastes, and are just as easy to apply, but unfortunately they are also more expensive.
Carbon-based pastes feature small carbon fibers in them. They are not the best at transferring heat, but they have a good density to them, so they are easy to apply without worrying about them spilling over. They are not electrically conductive, so if they did spill, there generally wouldn’t be any issues. While they won’t offer the lowest temps around, they are good for beginners to use.
Diamond-Based are some of the best ‘standard’ thermal pastes you can buy. They contain diamond powder which is absolutely amazing for transferring heat. Diamond pastes have a low viscosity which is good for filling in those smaller gaps of air and, as it is just diamond powder, it won’t scratch your CPU or heatsink.
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How long does thermal paste last?
Thermal paste is a vital component of any CPU cooling solution, but here’s how long you can expect it to last
Which is best for me?
There are many to choose from with different advantages
There are a few factors to consider when deciding which thermal paste is best for you. First, are you looking for thermal paste for a GPU or a CPU? Next, are you after the best heat transfer at all costs? There are both pros and cons when considering if a standard thermal paste or liquid metal is best for you. If you are unsure, it is likely best to go with a paste that is not electrically-conductive.
If you are just looking for something to get the job done without breaking the bank, something like Arctic’s MX-6 thermal paste or other carbon-based equivalent would be a great place to start. It is easy to use, offers great heat transfer, and can generally be found at a decent price.
Should you be looking for a liquid metal paste, one such as Thermal Grizzly Kryonaut will be a good choice. This is definitely for more advanced users, due to the dangers of spillage. But those who are into things like delidding their CPU and using a custom-loop, there is no denying the improvements in temperature when using it.
It’s always going to be a hard choice, but at the end of the day, most thermal pastes work well. While I personally prefer to apply my own, even using the pre-applied stuff on most heatsinks will do the trick. Just remember that they can dry out over time and should be changed now and again to make sure they are doing their job as best possible.
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How to clean thermal paste from CPU
Removing the thermal paste from your processor is a simple task. Here’s how to do it.