What is thermal paste used for? Thermal paste for the processor: which is better and why is it needed? Would toothpaste be fine?
Today we brought a computer for diagnostics with a suspicious malfunction; it turns off when you launch the chrome browser or some other program. As the owner of the computer said, he had already given it to two technicians, and they said that the motherboard or processor was faulty. In short, I accepted it and put it on diagnostics under the load of the aida64 program, it worked for about an hour and then turned off blue screen did not output, but immediately turned off. I threw in a known working power supply, the situation did not change, I turned it off in the settings automatic reboot when an error occurs in the hope of surprising the error code Bsod, but this didn’t help, somehow I didn’t look at the processor temperature, but then I looked and aida64 showed 119 degrees and the computer turned off, well, I think you need to raise the processor heatsink and see what’s under there it and when I picked it up I saw a thick layer of thermal paste KPT8, before that I had never seen such a thick layer of thermal paste.
What is thermal paste for?
If you tell in simple language, then thermal paste is needed to ensure good thermal contact. The processor cover looks like it has a smooth surface, but this is not the case, when you install a heatsink on the processor dry, due to the roughness and unevenness of the surface, microvoids remain, in which air remains and in these places there will be poor thermal contact, and when we apply special thermal paste, then These voids are filled with thermal paste and contact with the radiator in these voids occurs through the thermal paste. Well, something like this.
To apply thermal paste we need a plastic card, either a SIM card or bank card expired and you can still use your index finger, I always use it. I don’t recommend a tube of thermal paste, KPT 8, it dries quickly. Take any electronics except KPT8 from your nearest electronics store. Apply a small drop of thermal paste to the center of the processor and spread a thin layer over the entire surface of the processor, the thinner the better, but without gaps, if the radiator has a copper core, then you can apply thermal paste directly to the core and when you install the radiator in place, you need it Twist a little so that excess paste comes out. And don’t watch all the smart guys on YouTube how they show off how to apply the paste, there is one rule to apply it in a thin layer, and it doesn’t matter how you do it, when installing the radiator, the excess will be squeezed out.
– Igor (Administrator)As part of this review, I will tell you what thermal paste is, as well as about the features associated with it.
The central processing unit in a computer gets hot, especially under high loads, and therefore needs to be cooled. And in this part, no one will be surprised by the presence of a radiator, just as it is used with any other heating equipment. As they say, it is common knowledge that this “somehow” allows one to reduce the temperature. However, why do you need thermal paste and what is it for many? ordinary users not known.
But first, a little theory. In physics there is such a thing as thermal conductivity. Thermal conductivity is the ability of a substance to transfer heat from hot to cold. For reference, this characteristic is measured in W/(m*K). The higher this value, the faster the substance transfers heat.
To make it easier to understand, imagine that you are dipping a wooden and metal stick into boiling water. The thermal conductivity of the first is significantly lower than the second, so a metal stick will be hot after just a few minutes, but a wooden one will take a long time to heat up.
Why is this, since the processor and radiator seem to consist of metals and their alloys? The point is two important nuances. Firstly, air has extremely low thermal conductivity (for reference, this is why double windows allow for a long time keep the room warm). Secondly, there are no perfectly smooth metal surfaces. Therefore, if the processor is pressed against the heatsink, there will be cavities with air between them, through which heat will be poorly transferred.
To solve this problem, use thermal paste, the thermal conductivity of which is higher than that of air, and which fills all the uneven surfaces of the processor and radiator, which allows the computer’s central processor to be cooled more evenly.
Note: There are other nuances, such as diffusion of metals, electric currents and so on, but in computers heat transfer is more important (usually processors are covered with insulating material).
Note: It is worth considering that some thermal pastes may contain metal particles, so it is extremely important that the paste does not come into contact with the processor contacts.
For reference. IN general case In addition to thermal paste, hot-melt adhesive can also be used (additionally, like regular glue, it holds two objects together), thermal pads (additionally provides electrical insulation; less effective than paste, but due to its elasticity it allows filling voids in connections with complex terrain), liquid metal ( provides better thermal conductivity, but involves a lot of nuances).
How to properly apply thermal paste to a processor? It is very important to remember that the layer should be thin. In this case, the rule “more is better” is incorrect. The fact is that the thicker the layer, the worse the heat transfer from the processor to the radiator. Also, before attaching the radiator, the thermal paste should already be evenly distributed over the processor (it does not need to be applied to the radiator). If you try to first apply a drop of paste and then press the radiator, the paste will not be distributed evenly and voids will appear between the radiator and the processor (at the edges). To understand, imagine that you dropped milk on the tablecloth, and then pressed it with your palm and released it. You will see that the drawing will be uneven.
How often should you change thermal paste? In general, it is considered good practice to replace the paste once every year or two (for laptops once a year). However, this still very much depends on the paste itself (some pastes do not lose their properties for more than 3 years) and the conditions of use (for example, under constant high processor load, the paste dries out faster).
Note: In fairness, it is worth noting that a considerable number of old computers have never seen a single paste replacement in their lives. However, this had virtually no effect on performance.
Sooner or later, every user is faced with the problem of loss of computer or laptop performance. Often the cause of deterioration in equipment performance is clogging of microcircuits or the blowing system, as a result of which the efficiency of the cooling process is lost.
Second possible reason Overheating can cause the special thermal paste to dry out. As soon as the thermal conductive paste dries and cracks, the heat flow from the running processor slows down, which leads to constant overheating and unstable operation of the laptop.
What is thermal paste?
Thermally conductive paste is a plastic substance, most often a white or gray homogeneous mass, which is characterized by high thermal conductivity. The purpose of thermal paste is to improve heat transfer between components that actively generate heat and the fan (cooler). Simply put, the presence of paste ensures timely heat removal from the running processor to the cooler.
Thus, the heat generated during operation is transferred to the cooling device, preventing overheating of the components. Until recently, when processors were not as powerful as they are now, there was no urgent need for thermal paste. But today it has become an indispensable element powerful processors, intensively generating heat during operation.
How to choose thermal paste?
When choosing thermal paste, you should pay attention to the basic requirements for it. Thus, the paste must have a high degree of thermal conductivity, while demonstrating resistance to oxidation and anti-corrosion properties. Good pastes are resistant to high temperatures (from 70 degrees), and they are also dielectrics, that is, they have a low degree of electrical conductivity.
An important criterion is the presence of water-repellent properties. The paste itself must be produced on a non-drying basis, which will ensure a long working life of this substance. Also, given the length of time the user spends at a computer or laptop, thermal paste should be as harmless as possible to his body.
Replacing thermal paste
As already mentioned, high-quality thermal paste combines the processor and cooler into a single whole, while ensuring a heat transfer rate sufficient for normal cooling. An important condition is the timely replacement of heat-conducting paste that has exhausted its service life. There is no clear answer to the question of how often you should change toothpaste.
To prevent processor overheating, some experts recommend changing thermal paste every year. By and large, it all depends on the brand of paste and its characteristics. There is also a dependence on the loads to which the computer is exposed. Serious loads can ultimately lead to overheating, which means a decrease in the properties of the thermal paste, causing it to dry out faster and require regular replacement.
Some pastes, during normal processor operation, can retain their properties for more than four years, and some need to be replaced every year. Under normal operating conditions, the thermal paste on the video card requires replacement somewhat less frequently than the thermal paste on the processor. In order to track this moment, you need to monitor the operating temperature of the computer.
Remember: it is especially important to do this during the summer heat. The most convenient way to monitor the temperature of your computer is to use special programs. It is widely believed that a processor temperature of 70 degrees and above is critical. If such an increase in temperature is observed constantly and the thermal conductive paste is not changed in time, then the laptop or computer will constantly overheat and turn off.
Before applying thermal paste to the processor, you should figure out how often this is done and why. The next step is the correct choice of insulating material. And finally, the last thing is the application process itself, which is relatively simple, but still requires compliance with certain rules that are not always known to non-specialists.
The need to change thermal paste
The processor is one of the most important parts of a computer. With its help, millions and even billions of operations are performed per second, resulting in overheating. The use of fans with radiators helps to avoid a critical situation when the processor temperature leads to malfunctions. Excess heat is transferred to the cooler, closer contact with which is ensured by a special insulator - thermal paste. The same goes for a video card that overheats during prolonged use (except for options with passive cooling, when the radiator is already attached to the GPU).
If the paste is not used, something like the following may happen:
- An overheated processor will cause the system to freeze, reducing usability and even leading to the risk of losing information;
- The motherboard will completely fail, leading to the need for serious computer repairs.
The first time the paste is applied immediately after installing the processor on the board, if the assembly is done independently. For a PC that has already been assembled and is under warranty, and especially a laptop, this should not be done because of the possibility of losing the right to free service.
In the future, thermal paste is changed on average once a year for powerful and, especially, overclocked processors, both central and graphic. For lower-performing chips, the material can be applied less frequently. The reason for early replacement is slowdown of the device, unexplained reboots and freezes.
When choosing an insulator suitable for lubricating a processor, you should not pay attention to cheap options like KTP-8. Moreover, the thermal paste market has more effective materials created over the past few years.
Most of the materials are made using silicone and zinc oxide. Although the packaging of some types of pastes contains information about the presence of silver, ceramic or carbon particles in the composition. They increase the contact area between the processor and the heatsink, increasing system reliability.
Note! For the most powerful processors, it is worth using materials containing copper and gold. These metals have the highest thermal conductivity among all that paste is made from.
Application stages
Even knowing how to apply the paste correctly and having the right material, you can make a mistake that will lead to disruption of the processor. Therefore, during the work process, certain rules should be observed:
- The paste is applied evenly and distributed over the entire area of the lubricated processor and that part of the radiator that comes into contact with it;
- The thickness of the layer should be minimal - almost transparent, allowing you to see the symbols written on the part;
- There cannot be gaps or breaks in the thermal paste, leading to a decrease in contact.
Step 1. Preparatory work
Before starting work on lubricating the processor, you need to disconnect it from the network and remove all parts that prevent you from getting to the chipset itself. Including the wall system unit, radiator and its cooler. For a laptop, you must additionally remove the battery.
Step 2. Cleaning up old residues
After removing the cooling system, remove the remains of dried material left over from the last time. They also do this with a new processor that has already had thermal paste applied - usually the cheapest and most ineffective options are used when selling.
Important! To remove paste from the chipset and radiator, you must use cotton swabs or cotton napkins.
The easiest way to remove grease is to use isopropyl alcohol or an alcohol solution (70–90%) in which the materials used for wiping are wetted. For insulator that has not completely dried, you can also use a ruler, and for hardened insulator, you can use a regular school eraser. Last method It takes a relatively long time to polish the metal part until it shines, but as a result the processor remains intact.
The need for careful removal is caused by uneven surfaces of the processor and radiator, as a result of which microscopic particles may remain on them, negatively affecting thermal conductivity.
Step 3. Application and distribution of material
The first stage of application is to place a small drop of paste in the central part of the surface of the part to be lubricated - that is, the processor. The cooler radiator does not require lubrication at all, since it has an area larger than the total contact surface. And by applying an insulator to it, you can waste extra material and even short-circuit the contacts on the motherboard.
Distribute the paste over the processor using:
- A plastic card or other small object of the same thickness (for example, a SIM card);
- A special brush (spatula), sometimes sold together with thermal paste or purchased separately;
- Wear rubber gloves on fingers.
If material accidentally leaves the processor, it should be carefully removed using a special solution.
For each type of paste, the answer to the question of what layer to apply it with is different. For ordinary material this is approximately 0.5 mm. For paste containing precious metals, about 1 mm. Sometimes one drop squeezed out of the tube may not be enough to lubricate. In this case, apply a second one and repeat the same steps.
Step 4: Shut down
Once the paste is applied, the job is finished. Now you need to install the cooler on the chipset until the special fasteners snap into place and return the entire structure to motherboard. After this, the fan is connected to power, and the computer or laptop is put back together.
After turning on the PC, you should check in the BIOS how many degrees the system shows. On average, the processor should heat up to no more than 40 degrees. For AMD or Semptron models, temperatures up to 60–90 degrees are allowed.
Overheating of the computer, causing the system to freeze, interferes with work or gameplay (given that both the CPU and GPU are under high load during gaming). And in order to avoid such a situation, you should, first of all, apply thermal paste on time. Secondly, carry out preventive maintenance by ensuring proper care of the insides of the device - removing dust from time to time and cleaning the ventilation holes. And for PC users who are doing this kind of work for the first time, it’s worth checking out the video clip showing how to apply the paste correctly.
In this article I will try to give as much of the necessary theory as possible. If you want to understand once and for all what thermal paste is, what it consists of, what purpose it serves, and how to properly apply thermal paste to a processor and video card, you definitely need to read this material.
Why know all this? Knowledge of the theory will allow you to understand the principles of working with thermal interfaces. This means you will have a good understanding of what happens to your components when heated, using different thermal pastes, cooling systems, etc. Knowledge is power!
It is also important to understand this because when it overheats, the computer begins to work intermittently and unpleasant brakes appear in operation. Some of them can be removed using, but no program can replace the thermal paste on the processor for you.
This article does not claim to be scientific. In it I want to convey the basic concepts in simple words. Therefore, I ask physicists, electrical engineers and other specialists not to faint from the phrases and concepts used. If you see an error of fundamental importance, please write it in the comments. Thank you in advance:).
The concept of thermal conductivity of materials
Thermal conductivity is the ability of materials or gases to transfer heat from hot to cold. This is a quantitative characteristic that is similar to the concept of conductivity in electrical engineering. Unit of measurement – W/(m*K) – thermal conductivity coefficient.
To better understand what we are talking about, pay attention to the diagram:
As you can notice at copper thermal conductivity coefficient is 2 times higher than that of aluminum. This means that in the same time, 2 times more heat will pass through copper than through aluminum.
How to apply this in life? Understanding that a copper cooling system is almost 2 times superior to an aluminum one, we understand why it is so expensive. And we understand that it is copper that needs to be used when we use “hot” or overclocked processors.
Also note that you have air The thermal conductivity coefficient is on average 0.022 W/(m*K). What does it mean?
Almost no heat is transferred through air.
It is a kind of insulator. Many private houses, as you know, use this property of air for thermal insulation. The inner wall is laid out, then there is an air gap, then the outer wall is built. Thus, the air located between the two walls insulates the house from the cold or, conversely, the summer heat.
What is thermal paste
Thermal paste is a multi-component heat-conducting composition that is applied between the heated element and the heat-removing radiator or cooling system.
Thermal pastes, or thermally conductive compounds, are divided into 3 main groups:
- Heat-conducting paste-like compositions;
- Heat-conducting paste-like compositions, including glue (adhesive pastes);
- Liquid metal.
Purpose of using thermal paste
Thermal paste is used to replace air between contacting surfaces, thereby increasing thermal conductivity. For what? Let's remember what thermal conductivity coefficient air has? That's right, extremely low. Or almost none. Now let's look at the following diagram, which shows the thermal conductivity of modern thermal pastes and liquid metal.
As you can see, the thermal conductivity coefficient of even the cheapest and most common thermal paste KPT-8, almost 31 times higher than air. Now I think you understand what this means.
Understanding this brings us to the next question - how to apply thermal paste correctly?
Pay attention to the diagram below and think about why thermal paste needs to be applied in such a thin layer to the processor and cooling system.
I hope that you have already come to the right conclusion yourself. So, let’s approach this issue in detail, from a scientific 🙂 point of view, and apply logic.
Recently the thermal spreader on the processor or GPU video cards are made of copper.
The pyatak, or cooling system substrate, which is in direct contact with the surface of the processor, is made of aluminum. More expensive models are made of copper.
For example, let’s imagine that our entire cooling system is rich, made of copper. The thermal conductivity coefficient of copper is 400 W/(m*K). It turns out that if these two surfaces, the processor and the cooling system, are perfectly adjacent to each other, we will get effective heat dissipation.
But, unfortunately, it is almost impossible to ensure that the surfaces are in perfect contact with each other. And where they are loosely connected, air gets in. What is the thermal conductivity of air? 0.022 W/(m*K). This is in 18,181 times lower than copper. It turns out that in places where air enters, heat is practically not transferred.
And this is where thermal paste comes to our aid. As you remember, its thermal conductivity is 31 times higher than air, and expensive thermal pastes such as Arctic MX-4 are 386 times higher. So when you apply a thin layer of thermal paste, it fills in the uneven areas, displacing air. At the same time, copper surfaces have a maximum contact area, which means higher thermal conductivity.
On the other hand, you can fall into a trap. If you apply too little thermal paste, it will not be able to fill uneven surfaces and there will be poor heat transfer. Therefore, it is recommended to level the surface of the cooling system substrate and heat spreader on the processor or video card in advance.
Read more about applying thermal paste to the processor.
How often should you change thermal paste?
The thermal paste contains microdispersed powders of metals, microcrystals, nitrides or oxides of zinc and aluminum. To make a paste out of it, synthetic or mineral oils are used. They evaporate over time, and the thermal paste becomes less viscous and loses its properties.
Therefore, it is recommended to change it regularly. For example, it is recommended to change thermal paste KPT-8 or KPT-19 (it has higher temperature characteristics) once a year. Considering its low cost, this can be done more often.
Which thermal paste to choose
It depends more on your budget. Arctic MX-4 is considered the top thermal paste. It has a high thermal conductivity coefficient - 8.5 W/(m*K), and a long service life.
The most common and quite high-quality is KPT-8 or KPT-19. Low cost allows you to change it regularly. Its characteristics are sufficient for most modern computers and laptops.
