Sunday, November 27, 2022

How to install the power supply correctly


Over the past decade, many different power supplies have appeared on the market with active, semi-passive and passive cooling systems. Let’s figure out how best to install the power supply, depending on its cooling system and what threatens its incorrect installation.

Installing a power supply in the recent past
In the past, users didn’t have much choice when installing a power supply into a case. After all, in the 90s and zero years, the AT and ATX form factor standards reigned on the market, in which the power supply was usually installed in the upper part of the case. The PSU also took an active part in the cooling of computer components, pumping heated air from near the processor space through itself.

While the heat dissipation of processors and video cards was 30-50 watts, no problems arose. However, the temperature regime in the case and in the power supply increased along with the heat dissipation of the system components. Therefore, in 2004, Intel proposed the BTX standard, designed to improve the quality of cooling in the system unit, but it never became widespread.

However, the cases and the power supplies themselves began to change. Increasingly, fans with a diameter of 120-140 mm began to be used, becoming almost the standard in PSU cooling. Gradually, the landing site of the power supply moved to the coldest place in the case – down.

Popular case Cooler Master 690 II Advanced, 2010.

Power supplies have increased in power every year. If in the early 2000s the real power of mass power supplies was 150-200 watts, then by the beginning of the 2010s the power increased to real 300-450 watts, which were labeled as 450-600 watt models. There were also power supplies with a passive cooling system. For standard ATX cases, manufacturers usually took the cooling system out of it, for example, like Thermaltake Silent Purepower Fanless Heatpipe Cooling .

Cases with a lower location of the power supply made it possible to more efficiently cool the PSU itself. Therefore, models with semi-passive and passive cooling systems have gained popularity.

Now, before the user assembling a computer, questions arise – how to install a power supply? Fan up or down? And if it is completely without a fan – with a passive cooling system? Let’s figure it out.

What is the danger of heating the power supply

To begin with, it is worth understanding how dangerous the heating of the power supply is. If we open a typical PSU, we will see a whole scattering of capacitors. The stability and power quality of the computer directly depends on them. Capacitors are designed for fairly high temperatures, in the region of 85–105 degrees.

However, over time, under the influence of high temperatures and with cooling worsening due to dust, capacitors degrade. Sometimes they simply “dry up” – they lose electrolyte, sometimes they swell and even burst, and the electrolyte flows out. Degradation of capacitors in the standby power circuit can cause problems with turning on, and then supplying current with a voltage above 5 volts, which is guaranteed to ruin the motherboard.

Degradation of filter capacitors in a 12 volt supply circuit will generally cause a sharp increase in voltage ripple. This will destroy other capacitors: in the power circuits of the video card and the motherboard.

Manufacturers often save on the quality of capacitors, especially in inexpensive models, so the issue of cooling the power supply should be approached very seriously. After all, the life of much more expensive components, in fact, depends on it.

Do not forget that the higher the temperature of the air entering the power supply and the higher its heating, the lower its efficiency. When testing a power supply for compliance with the 80 PLUS standard , an inlet air temperature of 23 degrees is used.

However, independent experts, for example, from Hardwaresecrets , testing power supplies at elevated air temperatures of 45-50 degrees, come to the conclusion that in such harsh conditions, many power supplies do not reach the 80 PLUS certificate in terms of efficiency .

How to install a PSU with a constantly running fan
If you have an old form factor case where the power supply is located on top, then you have no choice. The power supply will take an active part in cooling the computer, pulling out heated air.

For office computers with low-power components, this is not critical. But if you have a powerful gaming PC, then it is advisable to change the case to one where the power supply is at the bottom, or at least improve the cooling in the case by putting a high-speed fan on the blower.

If you have a case with a bottom power supply and have a choice of how to install it, a dilemma arises. When you put the power supply with the fan up, the cooling in the computer case is slightly improved, and the presence of dust filters in the case reduces dust on the power supply. But at the same time, the temperature of the PSU increases, especially if there is a “hot” video card. Its noise will also increase if the unit is equipped with a temperature control. And the standard situation – the fall of the bolt that secures the video card down, turns into a big problem.

Most experts and experienced users agree that it is better to put a conventional power supply with the fan down.

How to install a PSU with a passive cooling system
This is a more complicated question, but often the manufacturer indicates the installation option on the power supply itself. Usually it is placed with the radiator up, allowing the heated air to rise unhindered.

For example, the Seasonic SS-460FL ( X-460 Fanless ) even has a sticker strictly warning of only one installation method. Therefore, when purchasing a power supply with a passive cooling system, download its data sheet in advance and check whether your case is suitable for it.

Power Supply Seasonic Platinum 400 Fanless [SS-400FL2]
How to install a PSU with a semi-passive cooling system
But this is the most difficult question that does not have an unambiguous solution. The fact is that each model of such a power supply has its own algorithm for turning the fan on and off depending on the load and / or temperature. It is necessary to take into account what load and how long it will be applied to the power supply. If it is lightly loaded most of the time and the fan does not rotate, then it is better to put it with the fan up for free convection of heated air.

Imagine a situation: a fairly powerful power supply with a semi-passive cooling system and a power of 850 watts – Corsair RM850i ​​- is used in two computers with different scenarios.

Corsair RM850i ​​Power Supply [CP-9020083-EU]
One is for heavy workloads, such as video encoding or computing on a multi-core processor and a powerful video card, and sometimes for web surfing and simple games. The second is mainly for web surfing and watching movies and no more than a couple of hours a day for games with a serious load.

According to the manufacturer, the Corsair RM850i should be passively cooled if it uses up to 40% power (350 watts) at 25 degrees.

But in the reviews they write that the fan starts at a higher load.

Obviously, the first option for using a PC will require almost constantly active cooling and it is better to put the Corsair RM850i ​​with the fan down. And in the second use case, most of the time it will work in passive mode and it is better to install it with the fan up.

If you are in doubt about what types of loads will be constant for your power supply and whether they will be able to use the active mode, then you should put it with the fan up. This mode is more versatile and safer in the case of a semi-passive cooling system.

The nuances of installing a PSU in cases with casings above it
Increasingly, there are cases with decorative casings above the power supply, such as Deepcool MATREXX 55 .

Obviously, if you install a power supply with a passive / semi-passive fan cooling system to the top, hot air convection will be extremely difficult – the PSU will overheat. Even if there is perforation on the casing, it will still be an obstacle that impairs cooling. If you have such a case, remove the shroud or install the PSU with the fan down.

Installation in cases of unique or rare design
There are many cases on the market with rare designs, such as cubic, thin slim cases, models where the power supply is in front or sideways, etc. For such cases, you can give advice – to choose a power supply more carefully. Consider how air flows will behave when ventilating such a case.

Housing Lian Li PC-Q37WX

Housing LIAN LI PC-Q37WX black

[compact (SFF), Mini-ITX, USB 3.2 Gen1 Type-A]
Power supplies with ultra-low speed cooling system
A power supply unit whose fan rotates at low load and low temperature at very low speeds, around 500 rpm, can save you from many problems.
In terms of noise, such a power supply is practically not inferior to models with a passive and semi-passive cooling system, but it is free from overheating problems.

For example, be quiet! Dark Power Pro 11 500W , whose fan rotates at low loads from 500 rpm and reaches only 1000 rpm at full load.

be quiet! Pure Power 11 500W [BN293] 5 799 *
As you can see, installing a power supply in a case is a rather difficult question, sometimes it is impossible to answer unambiguously. It is best to read the reviews on the case and power supply you are interested in in advance, and also ask the owners of these models for advice on the forums


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