Any of you who have ever worked on a PC or notebook have already come into contact with it. We're talking about the thermal paste. It is essential for the stable operation of a CPU or GPU, because optimal cooling is only possible with the paste.
In this article we will take a closer look at why you need it, what you should take into account when applying it and what special features apply to liquid metal.
Why is thermal paste even necessary?
If you ask this question, you will probably often hear that the thermal paste is intended to ensure better heat transfer from the chip to the cooler. That's not fundamentally wrong, but there's more to it.
Both the bottom of a cooler, even if it is nickel-plated, and the heat spreader of a CPU are not as smooth as they look at first glance. Under the microscope, the surfaces look almost like a lunar landscape, with small depressions everywhere.
And this is exactly what these deepenings are about:The thermal paste fills the small craters on the surfaces of the heat spreader and cooler base. This is the only way to achieve optimal heat transfer from the chip to the cooler over the entire surface.
How do I apply the thermal paste correctly?
Now that you know what the paste is for, you may be wondering how to apply it correctly. This question is almost a question of faith, some simply place a small dab in the middle of the heat spreader, others apply an X and others spread it over a large area.
But first things first:
Clean surface: In the first step, the surfaces of the CPU heat spreader and the bottom of the cooler must be clean. Removes any remaining old thermal paste that may still be present. It also doesn't hurt to clean brand new hardware with alcohol to remove any manufacturing residue. I always like to use isopropanol for this.
Apply thermal paste:I assume that any necessary attachment for the CPU cooler has already been installed. If this has happened, you can apply a little thermal paste to the heat spreader. In the first step, little means no more than a grain of rice. If that's not enough, you can always use a little more later.
The amount used is important to achieve a good result. You should know that even the thermal conductivity (W/m*K) of the best pastes is significantly lower than that of copper. By the way, the unit W/m*K stands forWatt pro Meter-Kelvin
.
An example:
- Good thermal paste: 12W/m*K
- Liquid metal: approx. 70 to 80 W*mk
- Aluminium: 220 W/m*K
- Kupfer: 380 W/mK
- Silber: 429 W/m*K
So you can see that even a very good thermal paste has poor thermal conductivity compared to aluminum or copper. Things look better with liquid metal, which performs better than normal paste, but still doesn't even come close to the thermal conductivity of aluminum.
This is exactly the reason why you should apply thermal paste as thinly as possible. If the layer is too thick, it has an insulating effect and this significantly impairs the performance of the entire cooling system. How you ultimately apply the paste is up to you.
Are you also interested in how heat pipes work? Here is the relevant article:
Intel recommends a dab in the middle, but I personally prefer to spread the paste very thinly on the heat spreader. When applying, however, it is important to ensure that there are no trapped air bubbles, which can also have a negative impact on performance.
When does thermal paste need to be replaced?
There is no hard and fast rule, but at some point the paste will start to dry out and then it should be replaced at the latest. However, it usually takes a few years for this point to be reached. Just keep an eye on the temperatures, if they start to rise for some inexplicable reason and the radiator is free of dust, it may be worth replacing the paste.
If you want to use liquid metal, there are a few additional things to consider. The liquid metals currently available commercially are generally based on gallium and indium.
Gallium in particular has the unpleasant property that it is not compatible with aluminum. If the liquid metal comes into contact with aluminum, corrosion occurs after a short time and the material becomes brittle.
In addition, liquid metal is electrically conductive. A tiny droplet on your motherboard or graphics card can mean the end of the expensive hardware. Liquid metal should therefore only be used by users who know exactly what they are doing. The material is definitely not suitable for beginners.
You have to be very careful when applying it, liquid metal is relatively difficult to spread and tends to form beads. If you have taken too much, you can use a syringe to suck it up from the surface.
If you have completed the procedure without an accident, you should be rewarded with lower temperatures. Since the thermal conductivity is still significantly lower than that of copper, you shouldn't expect miracles.
Write in the comments what experiences you have had with liquid metal.
