PC Buyer's Guide: cooling
Hello! In the last issue of the PC Buyer's guide, we briefly reviewed modern motherboards, chipsets, sockets, as well as a quick glance at the market for modern processors. We will talk more about the “fiery engines” another time, but today we are faced with a slightly different topic, which is directly related to both the personal comfort of the PC user and the health of the “iron horse”. It's about cooling systems for various components.
In this world, there are laws of physics, and some of them prevent us from flying on a swing in space, go “free” on vehicles, infinitely increase PC performance and do many other cool things. Fortunately, these same laws do a lot of other useful work, and we cannot take and refuse them, so we will have to adapt.
Our computer is (so far) not quantum, but semiconductor. It works by “switching” transistors from one state to another. The transistors themselves are many varieties, but that's not the point. To "switch" the circuit from one state to another, it is necessary to apply current to the control contact. The electric current in the metal is nothing more than the orderly movement of electrons. Actually, the electrons would be happy to move without any restrictions, but the inhomogeneity of the ionic lattice and the thermal oscillations of the ions themselves lead to the fact that some electrons transfer their impulse to the “environment” on the way to the target. The energy of their movement is converted into the internal energy of the crystal lattice, which leads to the heating of the conductor when an electric current passes through it.
')
Actually, the heating of the components is the result of the banal "friction" of electrons inside the conductor. Of course, there are materials that in conditions of very low temperatures practically do not have "friction" (superconductors), but working with them at home does not work out yet: they are expensive and require cooling to -150-200 degrees Celsius. And those that work at a relatively high temperature - and generally stand as a flight to the moon and back.
I would like to note another important fact. Although we have miniature processors, we can’t see the “conductor” in them without an electron microscope at all, “unwinding” the entire conductive loop of one processor can be done not in one kilometer or two kilometers. So a little bit here, a little bit there, but in the end the “slab” of 3x3 centimeters can warm up to a hundred degrees.
Engineers who develop microelectronics have long learned to count and predict heat losses in any parts of the circuit. All modern processors, the manufacturer indicates the so-called teplopaket : the maximum heat output from the thermal distribution cover (yes, the one on which thermal paste smear), under the maximum load when operating in normal mode.
Of course, the amount of thermal energy is measured in Calories or Joules, and power is measured in Watts, but these units of measurement are related (1 W ~ 859.84 cal / h), and in many other elements of electrical circuits, it is used Watts, so heat pack is recorded in watts.
What happens if the cooling system is not able to divert the required amount of energy from the processor? The processor trivially overheats, after which, at best, you will get a hang or reboot due to a triggered “fuse” that sent the system an emergency stop code for the OS, at worst, something inside the processor will break and you will have to buy non-profitable nanometer technology new processor .
The easiest way to cool the processor is to provide the thermal distributor with high-quality contact with the environment, the temperature of which will be much lower than the temperature of the radiator. Molecules (in the simplest case of air) will collide with a hot surface, pick up a part of the impulse that is much hotter (and stronger than the oscillating) molecules of the heat distributor. Less impulse - less oscillation - less surface temperature, which means that a hotter “filling” of the processor will again be able to “shake” the atoms and molecules in the thermal distributor so that it, in turn, transfers thermal energy to the environment.
To improve this type of cooling, you can increase the contact area of ​​the diffuser with the environment, and you can increase the "flow" of cold air molecules that will collide with the radiator. In fact, it is most effective to increase both parameters simultaneously.
Different metals have different coefficients of expansion, different electrical and thermal conductivity. The most effective cooling systems (of reasonable options, of course) are copper, but copper is a rather expensive metal, therefore it is used only in main heat-distributing structures (contact plates and heat pipes), and the “edges” of radiators are usually made of aluminum. Its characteristics are slightly worse, but quite acceptable. Of course, there are exceptions to this “rule”, but they are rare and do not interest us.
Heat pipes work as follows: inside there is a certain amount of liquid, which is easy to bring to a boil. After the thermal distributor reaches a certain temperature, the liquid begins to evaporate, take heat from the metal shell, after which the vaporous fraction “goes” to the cooler end, where it transfers thermal energy to the radiator, cools, condenses, then the process repeats. This approach can significantly accelerate the removal of heat from the processor, but it has one major drawback. The composition inside the tube begins to work at a certain temperature, and until a boiling point is reached, the thermal conductivity of this system leaves much to be desired. In addition to the "lower" threshold, another trouble awaits us "from above." By telling the system too much heat, we can evaporate all the liquid, and if the cooling system cannot quickly dissipate the received energy, the liquid will not have time to condense and the thermal conductivity of the entire system drops sharply, after which the entire processor quickly overheats. However, you can get problems from the boiling off of the heat pipes only if you indulge in overclocking and stubbornly ignore the readings of the temperature sensor.
In fact, the entire water cooling system (hereinafter referred to as SWO) is one large heat pipe, with the only difference that it does not boil, but is simply “pumped” around the closed circuit of the pump: it heats up on the processor and / or video card, it cools down on the radiator, which again required to blow air. Differences in details: external pump or "built-in", self-assembly system or factory, there is an expansion tank, or the whole "dropsy" works in a closed loop. Well, heat carriers may differ: someone uses alcohols, someone distilled water, someone special coolants.
The evaporative cooling system (with freon) will not technically differ from a conventional refrigerator: with the same success, you can buy a small refrigerator and assemble a computer directly in it. Energy costs, however, will not please. I didn’t see any factory-made, ready-to-install systems of this level for ordinary PCs in Russia, but such things are rare in thewild abroad. However, having direct hands and an old unnecessary refrigerator it is quite possible to “trick” such a thing on their own.
The trouble is that the usefulness of a freon for a home computer is generally questionable.
Liquid nitrogen cooling refers to evaporative systems, and has absolutely no benefit in a home computer, since the system is not closed and the fumed vapors just fly away, requiring constant refilling of the cooling cup. In addition, the snow coat of the moisture from the ambient air condensing on a glass requires appropriate insulation of the motherboard. The only purpose of nitrogen cooling is to achieve short-term record - breaking indicators of acceleration for competitive purposes; to ensure stable operation of the processor at a high frequency during a day / week / month, such a cooling system cannot.
This, in fact, may include oil-based immersion cooling systems (they were already told about them on GT and not only ) and the use of Peltier elements. With the first, everything is more or less clear; all components are placed in an “aquarium” with a large volume of liquid that does not conduct an electric current, and that’s all. The large volume of the heat carrier and its high heat capacity makes it possible to obtain a completely silent system unit.
Peltier elements are tricky devices that can either generate an emf (and therefore a current) when there is a temperature difference on both sides, or vice versa: waste electricity and “transfer” heat from one side to another, and the stronger the “hot” side is cooled, the the transfer will be more effective and the more “freezing” the side that takes heat from the processor / heatpipes will be. In my memory, there was only one monstro cooler with such a feature - Cooler Master V10 .
And I had it. It takes a lot of space, eats a lot of energy, the price is indecent, the use is dubious. For the same money, you could get an excellent “tower” cooler from Noctua and get about the same results.
To drive air through the system unit and blow radiators on the one hand, the task is simple. Put the planes at an angle, rotate them, they drop the air flow. In fact, in fanbuilding a million tricks. The correct motors, the best bearings, manual balancing, the cunning shape of the blades and the "notch" on the leading edge - all these parameters influence both the efficiency of the fan and the noise indicators.
If you divide very roughly, then all-all-all fans are divided according to the impeller diameter (standard 80, 92, 120, 140 mm, other values ​​are less common), the "thickness" of the casing and the impeller, the method of adjusting the rotational speed (PWM - pulse-width modulation, if in Russian, a resistive system that regulates directly the voltage on the motor winding or fixed speed in general) and the power connector. In addition, bearings are responsible for the noiselessness and durability of the fan. The most simple, cheap and "noisy" - rolling bearings. Balls roll in them in two rings, transforming sliding friction into rolling friction. Pros - low cost, ease of manufacture. Cons - so-so balancing, sensitivity to pollution. In more expensive models, different types of sliding bearings are used: hydrostatic, hydrodynamic, magnetic. They require special precision manufacturing and rather expensive materials, so they are used only in models of middle and higher price categories.
One of the best, in my opinion, manufacturers of “silent” and low-noise carolsons are Scythe companies (read “Sais”, and despite the fact that many people believe that Sais is no longer a cake, there are quite decent models) and Noctua. Of course, other vendors also have excellent specimens, but these two companies are actively promoting the idea of ​​"both quiet and cold."
By the way, Noctua usually use complex hydrodynamic bearings with magnetic stabilization, and Scythe, as a rule , the most simple - hydrostatic.
About thermal interface, or thermal paste - just a couple of words. I do not want to open the next gate to hell, comparing KPT-8 and AlSil / Arctic Silver, on this subject there are already enough copies broken in the runet, choose yourself (or rather, use what the manufacturer has attached to the cooler in the kit, while you are not overclocking - the possibilities of standard thermal interfaces with the head are enough). The essence and purpose of the thermal paste is to close microcracks and irregularities in the polished surfaces of the thermal distributor and the radiator contact pad. The absence of surface defects will prevent air between the processor and the radiator, which will play the role of a heat insulator.
The correct method of applying thermal paste is placed in one picture.
The most interesting section. Suppose you decide that you want a quiet and powerful computer. Where to begin? With the choice of cooling and processor for it, or vice versa?
In fact, it depends on what you need: a quiet or powerful computer. In the first case, you take some whispering cooling system, such as this :
Thanks for the picture for the resource overclockers.ru
Choose a processor affordable, preferably with a heat pack of 65 or 45 watts, so that the fan does not even think to accelerate under load, set a low-profile memory with radiators and enjoy the silence.
With the option "from performance" everything is somewhat more complicated. If you decide that you need a serious processor, say, a Core i7 or a top-end AMD FX-8300, and at the same time work at night next to sleeping babies, an evil mother-in-law or nervous grandmother, who “signals” computer’s signals from Mars to Mars will have to come with all care. True, and the money it will cost appropriate.
The thermal pack of top-end “consumer” processors, for example, the Core i7-4970K , in spite of all the advances in progress, nanometers, and other energy saving, is closely approaching the mark of 90-100 watts. Any tower cooler for 3,000 rubles will cope with such a load quite easily, but for quiet operation you will need something really cool.
One of the favorites, in this case, can be considered a kilogram monster Thermalright HR-22 . Issue price - completely inhumane ~ 8 thousand rubles. The dimensions are impressive.
At the same time you buy a passive radiator, without fans, able to do with natural convection and the air flow that the case fans provide. Unfortunately, building a computer with such a monster requires an excellent knowledge of the capabilities of your hardware and the proper organization of the “pulling” of the body itself.
Much less "zamorochennym" option is to install the Noctua NH-D14 or the older model D15. It costs a little less, about 7,200 rubles, complete - two fans with a diameter of 120 and 140 millimeters (in some cases 2x140), a full set of adapters, a long screwdriver and detailed installation instructions.
NH-D14 has been one of the coolest air coolers for many years in a row, it easily copes with overclocked processors, ensuring the removal of up to 200 W of heat, so that it will definitely control the “regular” i7 at night.
In the case, if you are building an inexpensive computer, but still want to remain in silence, you should pay attention to the Core i3 family of processors (they are quite cold with good performance, especially in home use) with a heat release of up to 45 watts. To cool the ardor of such a fiery heart is not difficult even for relatively inexpensive coolers:
Scythe Grand Kama Cross 2 is ready to work for ~ 2 800 rubles. A great quiet fan, simple installation, easy maintenance - unhooked the bracket, removed the fan, vacuumed it, put it back on.
Thanks for the picture overclockers.ua
As an even more inexpensive alternative, you can consider the Cooler Master S400 . It costs less than two thousand rubles, it doesn’t make noise, but now it’s not so easy to clean it after half a year. However, the installation of fabric filters on the ventilation of the case solves most of the problem: the "felt boot" accumulates on the easily accessible case cover, and not in the radiator slots.
Of course, do not forget about the factory SVO from Corsair or Thermaltake. Unfortunately, the price for them has never been humane, and taking into account the dollar exchange rate, I don’t want to voice these figures at all.
As strange as it sounds, the cooling of the processor is not the biggest generator of problems and noise. The loudest turbines are buzzing, driving air through discrete video cards. Unfortunately, it only remains to read reviews and reviews: vendors do their best to create non-standard design of printed circuit boards, various multi-fan cooling systems, but the laws of physics cannot be fooled: either a powerful video card or deathly silence. Stay in touch, the next article on power supplies is on the way.
In the meantime, you can read one of our previous publications:
» PC buyer's guide 2015: Motherboards, chipsets and sockets
» Twist-twirl, I want to confuse. Understanding the HDD lines
Where does the heating come from?
In this world, there are laws of physics, and some of them prevent us from flying on a swing in space, go “free” on vehicles, infinitely increase PC performance and do many other cool things. Fortunately, these same laws do a lot of other useful work, and we cannot take and refuse them, so we will have to adapt.
Our computer is (so far) not quantum, but semiconductor. It works by “switching” transistors from one state to another. The transistors themselves are many varieties, but that's not the point. To "switch" the circuit from one state to another, it is necessary to apply current to the control contact. The electric current in the metal is nothing more than the orderly movement of electrons. Actually, the electrons would be happy to move without any restrictions, but the inhomogeneity of the ionic lattice and the thermal oscillations of the ions themselves lead to the fact that some electrons transfer their impulse to the “environment” on the way to the target. The energy of their movement is converted into the internal energy of the crystal lattice, which leads to the heating of the conductor when an electric current passes through it.
')
Actually, the heating of the components is the result of the banal "friction" of electrons inside the conductor. Of course, there are materials that in conditions of very low temperatures practically do not have "friction" (superconductors), but working with them at home does not work out yet: they are expensive and require cooling to -150-200 degrees Celsius. And those that work at a relatively high temperature - and generally stand as a flight to the moon and back.
I would like to note another important fact. Although we have miniature processors, we can’t see the “conductor” in them without an electron microscope at all, “unwinding” the entire conductive loop of one processor can be done not in one kilometer or two kilometers. So a little bit here, a little bit there, but in the end the “slab” of 3x3 centimeters can warm up to a hundred degrees.
Heat pack
Engineers who develop microelectronics have long learned to count and predict heat losses in any parts of the circuit. All modern processors, the manufacturer indicates the so-called teplopaket : the maximum heat output from the thermal distribution cover (yes, the one on which thermal paste smear), under the maximum load when operating in normal mode.
Of course, the amount of thermal energy is measured in Calories or Joules, and power is measured in Watts, but these units of measurement are related (1 W ~ 859.84 cal / h), and in many other elements of electrical circuits, it is used Watts, so heat pack is recorded in watts.
What happens if the cooling system is not able to divert the required amount of energy from the processor? The processor trivially overheats, after which, at best, you will get a hang or reboot due to a triggered “fuse” that sent the system an emergency stop code for the OS, at worst, something inside the processor will break and you will have to buy non-profitable nanometer technology new processor .
Theory - Air Cooling
The easiest way to cool the processor is to provide the thermal distributor with high-quality contact with the environment, the temperature of which will be much lower than the temperature of the radiator. Molecules (in the simplest case of air) will collide with a hot surface, pick up a part of the impulse that is much hotter (and stronger than the oscillating) molecules of the heat distributor. Less impulse - less oscillation - less surface temperature, which means that a hotter “filling” of the processor will again be able to “shake” the atoms and molecules in the thermal distributor so that it, in turn, transfers thermal energy to the environment.
To improve this type of cooling, you can increase the contact area of ​​the diffuser with the environment, and you can increase the "flow" of cold air molecules that will collide with the radiator. In fact, it is most effective to increase both parameters simultaneously.
Different metals have different coefficients of expansion, different electrical and thermal conductivity. The most effective cooling systems (of reasonable options, of course) are copper, but copper is a rather expensive metal, therefore it is used only in main heat-distributing structures (contact plates and heat pipes), and the “edges” of radiators are usually made of aluminum. Its characteristics are slightly worse, but quite acceptable. Of course, there are exceptions to this “rule”, but they are rare and do not interest us.
Heat pipes work as follows: inside there is a certain amount of liquid, which is easy to bring to a boil. After the thermal distributor reaches a certain temperature, the liquid begins to evaporate, take heat from the metal shell, after which the vaporous fraction “goes” to the cooler end, where it transfers thermal energy to the radiator, cools, condenses, then the process repeats. This approach can significantly accelerate the removal of heat from the processor, but it has one major drawback. The composition inside the tube begins to work at a certain temperature, and until a boiling point is reached, the thermal conductivity of this system leaves much to be desired. In addition to the "lower" threshold, another trouble awaits us "from above." By telling the system too much heat, we can evaporate all the liquid, and if the cooling system cannot quickly dissipate the received energy, the liquid will not have time to condense and the thermal conductivity of the entire system drops sharply, after which the entire processor quickly overheats. However, you can get problems from the boiling off of the heat pipes only if you indulge in overclocking and stubbornly ignore the readings of the temperature sensor.
Theory - liquid cooling
In fact, the entire water cooling system (hereinafter referred to as SWO) is one large heat pipe, with the only difference that it does not boil, but is simply “pumped” around the closed circuit of the pump: it heats up on the processor and / or video card, it cools down on the radiator, which again required to blow air. Differences in details: external pump or "built-in", self-assembly system or factory, there is an expansion tank, or the whole "dropsy" works in a closed loop. Well, heat carriers may differ: someone uses alcohols, someone distilled water, someone special coolants.
The evaporative cooling system (with freon) will not technically differ from a conventional refrigerator: with the same success, you can buy a small refrigerator and assemble a computer directly in it. Energy costs, however, will not please. I didn’t see any factory-made, ready-to-install systems of this level for ordinary PCs in Russia, but such things are rare in the
The trouble is that the usefulness of a freon for a home computer is generally questionable.
A liquid nitrogen
Liquid nitrogen cooling refers to evaporative systems, and has absolutely no benefit in a home computer, since the system is not closed and the fumed vapors just fly away, requiring constant refilling of the cooling cup. In addition, the snow coat of the moisture from the ambient air condensing on a glass requires appropriate insulation of the motherboard. The only purpose of nitrogen cooling is to achieve short-term record - breaking indicators of acceleration for competitive purposes; to ensure stable operation of the processor at a high frequency during a day / week / month, such a cooling system cannot.
Other exotic
This, in fact, may include oil-based immersion cooling systems (they were already told about them on GT and not only ) and the use of Peltier elements. With the first, everything is more or less clear; all components are placed in an “aquarium” with a large volume of liquid that does not conduct an electric current, and that’s all. The large volume of the heat carrier and its high heat capacity makes it possible to obtain a completely silent system unit.
Peltier elements are tricky devices that can either generate an emf (and therefore a current) when there is a temperature difference on both sides, or vice versa: waste electricity and “transfer” heat from one side to another, and the stronger the “hot” side is cooled, the the transfer will be more effective and the more “freezing” the side that takes heat from the processor / heatpipes will be. In my memory, there was only one monstro cooler with such a feature - Cooler Master V10 .
And I had it. It takes a lot of space, eats a lot of energy, the price is indecent, the use is dubious. For the same money, you could get an excellent “tower” cooler from Noctua and get about the same results.
Fans
To drive air through the system unit and blow radiators on the one hand, the task is simple. Put the planes at an angle, rotate them, they drop the air flow. In fact, in fanbuilding a million tricks. The correct motors, the best bearings, manual balancing, the cunning shape of the blades and the "notch" on the leading edge - all these parameters influence both the efficiency of the fan and the noise indicators.
If you divide very roughly, then all-all-all fans are divided according to the impeller diameter (standard 80, 92, 120, 140 mm, other values ​​are less common), the "thickness" of the casing and the impeller, the method of adjusting the rotational speed (PWM - pulse-width modulation, if in Russian, a resistive system that regulates directly the voltage on the motor winding or fixed speed in general) and the power connector. In addition, bearings are responsible for the noiselessness and durability of the fan. The most simple, cheap and "noisy" - rolling bearings. Balls roll in them in two rings, transforming sliding friction into rolling friction. Pros - low cost, ease of manufacture. Cons - so-so balancing, sensitivity to pollution. In more expensive models, different types of sliding bearings are used: hydrostatic, hydrodynamic, magnetic. They require special precision manufacturing and rather expensive materials, so they are used only in models of middle and higher price categories.
One of the best, in my opinion, manufacturers of “silent” and low-noise carolsons are Scythe companies (read “Sais”, and despite the fact that many people believe that Sais is no longer a cake, there are quite decent models) and Noctua. Of course, other vendors also have excellent specimens, but these two companies are actively promoting the idea of ​​"both quiet and cold."
By the way, Noctua usually use complex hydrodynamic bearings with magnetic stabilization, and Scythe, as a rule , the most simple - hydrostatic.
Thermal paste
About thermal interface, or thermal paste - just a couple of words. I do not want to open the next gate to hell, comparing KPT-8 and AlSil / Arctic Silver, on this subject there are already enough copies broken in the runet, choose yourself (or rather, use what the manufacturer has attached to the cooler in the kit, while you are not overclocking - the possibilities of standard thermal interfaces with the head are enough). The essence and purpose of the thermal paste is to close microcracks and irregularities in the polished surfaces of the thermal distributor and the radiator contact pad. The absence of surface defects will prevent air between the processor and the radiator, which will play the role of a heat insulator.
The correct method of applying thermal paste is placed in one picture.
Practice
The most interesting section. Suppose you decide that you want a quiet and powerful computer. Where to begin? With the choice of cooling and processor for it, or vice versa?
In fact, it depends on what you need: a quiet or powerful computer. In the first case, you take some whispering cooling system, such as this :
Thanks for the picture for the resource overclockers.ru
Choose a processor affordable, preferably with a heat pack of 65 or 45 watts, so that the fan does not even think to accelerate under load, set a low-profile memory with radiators and enjoy the silence.
With the option "from performance" everything is somewhat more complicated. If you decide that you need a serious processor, say, a Core i7 or a top-end AMD FX-8300, and at the same time work at night next to sleeping babies, an evil mother-in-law or nervous grandmother, who “signals” computer’s signals from Mars to Mars will have to come with all care. True, and the money it will cost appropriate.
The thermal pack of top-end “consumer” processors, for example, the Core i7-4970K , in spite of all the advances in progress, nanometers, and other energy saving, is closely approaching the mark of 90-100 watts. Any tower cooler for 3,000 rubles will cope with such a load quite easily, but for quiet operation you will need something really cool.
One of the favorites, in this case, can be considered a kilogram monster Thermalright HR-22 . Issue price - completely inhumane ~ 8 thousand rubles. The dimensions are impressive.
At the same time you buy a passive radiator, without fans, able to do with natural convection and the air flow that the case fans provide. Unfortunately, building a computer with such a monster requires an excellent knowledge of the capabilities of your hardware and the proper organization of the “pulling” of the body itself.
Much less "zamorochennym" option is to install the Noctua NH-D14 or the older model D15. It costs a little less, about 7,200 rubles, complete - two fans with a diameter of 120 and 140 millimeters (in some cases 2x140), a full set of adapters, a long screwdriver and detailed installation instructions.
NH-D14 has been one of the coolest air coolers for many years in a row, it easily copes with overclocked processors, ensuring the removal of up to 200 W of heat, so that it will definitely control the “regular” i7 at night.
In the case, if you are building an inexpensive computer, but still want to remain in silence, you should pay attention to the Core i3 family of processors (they are quite cold with good performance, especially in home use) with a heat release of up to 45 watts. To cool the ardor of such a fiery heart is not difficult even for relatively inexpensive coolers:
Scythe Grand Kama Cross 2 is ready to work for ~ 2 800 rubles. A great quiet fan, simple installation, easy maintenance - unhooked the bracket, removed the fan, vacuumed it, put it back on.
Thanks for the picture overclockers.ua
As an even more inexpensive alternative, you can consider the Cooler Master S400 . It costs less than two thousand rubles, it doesn’t make noise, but now it’s not so easy to clean it after half a year. However, the installation of fabric filters on the ventilation of the case solves most of the problem: the "felt boot" accumulates on the easily accessible case cover, and not in the radiator slots.
Of course, do not forget about the factory SVO from Corsair or Thermaltake. Unfortunately, the price for them has never been humane, and taking into account the dollar exchange rate, I don’t want to voice these figures at all.
Results
As strange as it sounds, the cooling of the processor is not the biggest generator of problems and noise. The loudest turbines are buzzing, driving air through discrete video cards. Unfortunately, it only remains to read reviews and reviews: vendors do their best to create non-standard design of printed circuit boards, various multi-fan cooling systems, but the laws of physics cannot be fooled: either a powerful video card or deathly silence. Stay in touch, the next article on power supplies is on the way.
In the meantime, you can read one of our previous publications:
» PC buyer's guide 2015: Motherboards, chipsets and sockets
» Twist-twirl, I want to confuse. Understanding the HDD lines
Source: https://habr.com/ru/post/376895/
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