Feeding phases - quantity, practical benefit from quantity. Power phases for the processor on the motherboard - how much do you need? What kind of power supply is needed for a modern gaming pc How to find out the number of power phases of the motherboard

Now let's move on to an equally important part of any PC - the motherboard.

1. Color is important motherboard, and it is best to take black

A funny myth with a very simple history: large vendors such as Apple or Asus began to paint their expensive motherboards black about 10 years ago. Of course, they broke less than simpler "color" motherboards from competitors, hence the belief that "black goez fasta" came from. In fact, the color of the board can be absolutely any - yellow, green, white, blue, black - because this is a banal painting that does not in any way affect the internal characteristics of the PCB. So, for example, in the 90s, textolite was often not painted at all, and most of the boards - both expensive and cheap - had a dirty yellow color. So the difference between a black and white board is exactly the same as between a black and white iPhone - only in color and nothing more.

2. Heating the processor power circuits up to 90 degrees is a critical lot

Mosfets are highlighted in red - the hottest elements of the CPU power supply circuit.

Do not confuse the processor itself and its power supply circuits - indeed, for silicon CPUs, temperatures above 90-100 degrees are critical and will lead to its rapid failure. But this is not true for power circuits: so, the hottest part of them - the so-called mosfets (field-effect transistors with an insulated gate) - have operating temperatures up to 150-175 degrees, so 90 degrees on them, of course, is a lot, but not critical. All other elements of the power supply circuits, such as capacitors and chokes, heat up seriously less and are often not covered by radiators at all because of this.

3. Internal peripherals on boards are always of low quality and you need to buy them separately

A myth that goes back almost from the bearded 90s, when sound and network controllers on motherboards really left much to be desired. However, now this is not the case for a long time: 99% of boards are equipped with gigabit LAN controllers from Intel or Realtek, and taking into account that the speeds home internet on average, an order of magnitude lower, there will be no problems with them.

With the sound, everything is a little more serious - now the boards are mainly equipped with controllers from Realtek. I can't call them audiophile, but if you listen to music from streaming services and play games, there will definitely be no problems with sound quality.

4. Any expensive motherboards with a bunch of ports and heatsinks are not needed, since even the cheapest solutions based on the Z370 chipset support my Core i9 - I'll choose from them

Of course, there is always a desire to save money, and you can often take a cheaper board without, for example, built-in Wi-Fi or m.2 slots, saving up to a couple of thousand rubles. But, alas, further savings usually begin to affect the circuitry of the board - namely, manufacturers begin to reduce the number of CPU power phases on the board from 6-10 to 3-4. Why is this scary? If earlier the energy required to power the processor passed through 10 phases, heating them not very much, now it will pass through only 3 phases, which will increase the heating significantly. Plus the fact that cheap motherboards often do not even have the simplest radiators on the power supply circuits, they can easily heat up to 120+ degrees with top processors under load, which is already critical for them:

In addition, various negative effects begin: for example, overheating protection may work, which will reduce the voltage on the processor, which means its frequency and performance. Weak power circuits may initially not provide the voltage necessary for the top-end processor to operate under load, which again will negatively affect its frequency. So, alas, cheap motherboards are better left for simpler processors.

5. For top-end PCs, it is better to take full-sized boards

The myth, again, comes from the early 2000s, when compact motherboards began to appear - then manufacturers, in pursuit of size, could seriously curtail the functionality of such motherboards. But now this is not the case - of course, mini-ITX boards have only one PCIe x16 slot and usually two slots for RAM, but all other parameters - even the ability to overclock processors and an m.2 slot with NVMe support - may be present, so there are no problems to assemble a top-end PC with a Core i9-9900K and RTX 2080 Ti in a case with dimensions that are slightly larger than those of consoles.

6. Reinforced PCIe slots and RAM - marketing, they are not needed

In the past few years, various manufacturers have begun to reinforce PCIe slots and even RAM, justifying this by the fact that modern top-end video cards often weigh 1.5-2 kg, which can break the slot. However, here you need to understand a couple of things: firstly, this does not answer the question of why to reinforce the RAM slots, since even with heatsinks the dies hardly weigh more than a couple of hundred grams and will definitely not break the plastic in any way. Secondly, upon closer examination, it will be seen that the slot reinforcement of the board itself does not touch, that is, the slots are still held only on their own contacts:

I think you're under the impression that I'm contradicting myself and arguing that reinforcement is really marketing. However, this is not entirely true: in reality, under the weight of a heavy video card, the narrow slot of the plastic PCIe slot may widen slightly, which will cause the contact to be lost. Reinforcement will prevent this from happening - but, again, if you have a heavy video card, you should buy a special holder so as not to break the slot out of the board.

7. Mobile (SODIMM) RAM cannot be installed in the desktop board (with DIMM slots)

At first glance, it seems that this is not a myth - DIMM and SODIMM dies differ in size at times, so laptop RAM simply will not physically fit on a desktop board. But remember about SD cards - they also come in different formats, however, using an adapter, you can take a microSD and put it in a full-size slot, and it will work without problems.

With RAM, everything is exactly the same: electrically SODIMM from DIMM practically does not differ, so by purchasing the appropriate adapter, you can easily put laptop RAM into your computer, and it will work without problems. Of course, the question of the expediency of such a solution is open to question, but if you have an extra RAM plate for laptops lying around, and you have nowhere to put it, you can easily upgrade your PC with it.

8. If the processor power connector on the motherboard is 8 pin, then a 4 pin power supply will not work.

It should be understood that the 8 pin power supply on the board is simply 4 + 4 pin (this is hinted at by the fact that many 8 pin power supplies are just represented as 4 + 4), which are connected in parallel:

Accordingly, if you connect only 4 of 8 pins, then the motherboard will work without problems in most cases. Of course, you should understand that you should not seriously load the processor with such a connection - the "extra" 4 pins are just created in order to reduce the heating of the wires from the power supply unit and tracks in the PCB. But if, for example, you bought new board and CPU, but on new block power supply from 8 pin was not enough money - it is quite possible to “sit out” on 4 pin.

9. If the processor is not supported motherboard, then nothing can be done, you need to change the board

Usually this is still not a myth, but recently there are enough exceptions: for example, Xeon processors for the server socket LGA771 have become very popular, which often sell for several hundred rubles at various trading platforms. And they, with some desire (cutting the "ears" in a new place and soldering the conductor), can be put into ordinary desktop boards on LGA775:

Another exception is the LGA1151 and 1151v2 sockets: they differ mostly only in software, so with some "magic" with the BIOS, you can make 8th generation processors work on officially unsupported motherboards with 100 or 200 chipsets.

10. Updating the BIOS is a complicated ritual that should not be done on your own

For some reason, for many, the phrase "BIOS update" causes panic and the image of a stern bearded computer technician who conjures with floppy disks and prints some incomprehensible characters in command line... Fortunately, for the last 5 years this has not been the case for a long time - BIOS often have friendly user interface in Russian and support working with a mouse, and updating the BIOS is just a couple of mouse clicks, after which the necessary update will be downloaded from the Internet and installed by itself.

It is also believed that if everything works, then you should not update the BIOS. Again, this is not the case, because often new BIOS versions have various security fixes (such as patches against Meltdown or Specter), which should not be ignored. And even more so if the board does not work correctly - what happens if you bought it right after the release - often exactly BIOS updates will solve your problems.

11. All slots of the same type on the board are identical, you can use any

Not entirely true: so, usually only the PCIe slot closest to the processor can operate at a maximum speed of x16, the slots below often work only in x8 or x4 mode, so you should not use them with fast video cards:

The same applies to SATA: if you are using an m.2 slot with an NVMe drive at the same time, then one of the SATA connectors may be disabled (since the number of PCIe lanes in the chipset is limited), so do not be surprised that after installing a fast SSD in your computer for some reason your hard drive has ceased to be detected.

12. Motherboards from XXX are better than YYY

In general, such a comparison is incorrect, just like with other types of equipment. However, there are always brands that produce completely low-quality products: for example, in laptops, these are Digma and iRU. There is a similar division among motherboard manufacturers.

So, MSI, Asus, Gigabyte (as well as Supermicro and Tyan in the server segment) are considered good manufacturers: again, this does not mean that their motherboards are perfect, but still they usually have the least problems. ASRock, Colorful, Biostar, ECS are considered mid-level manufacturers - perhaps it makes sense to compare them with smartphones from Xiaomi: they seem to be cheaper than solutions from AAA brands, but they require some knowledge in order to configure everything as it should, and their BIOS at first may be raw ...

The rest of the motherboards, usually Chinese (from Xuanan) or from OEMs, are often very problematic: they are whimsical to RAM, respond incorrectly to buttons, can turn off during operation, etc. And, alas, there is no need to wait for software fixes - OEMs do not post them on the Internet at all, and you can get them only from new revisions of the board, and Chinese manufacturers usually “forget” about support.

13. Small boards (mATX, mini-ATX) cannot be installed in large cases (Full or Mid Tower)

The myth, again 20 years ago, when compact motherboards had just begun to appear, and the cases simply did not have mounts for them. However, now even the simplest "tin boxes" have such fasteners - another question is why take a spacious case and put a miniature board in it.

14. Boards for Intel processors better than AMD

The reason for this myth is quite understandable: usually at the start of sales with new AMD processors there are problems: for example, Ryzen was picky about RAM, and not all dies could work at least 3000 MHz. Intel processors are traditionally more stable in this regard, but, in any case, the problem here is software: hardware boards of the same level as for Intel processors, which for AMD usually differ only in socket and chipset - they are even very similar in appearance.

15. For any manipulation with the board, you need to remove the BIOS battery

Do not confuse disconnecting the board (that is, pulling the power supply cord out of the socket) with removing BIOS batteries- the latter is needed only in order to save BIOS settings if power is suddenly lost. Accordingly, the voltage from it goes only to BIOS chip, so you can safely assemble your PC with the battery inserted. The only exception is if you need to reset the BIOS settings: in this case, it is logical, you need to get the battery.

As you can see, there are many different myths about motherboards. Do you know any more? Write about it in the comments.

CPU power connectors

The CPU is powered by a device called the Voltage Regulator Module (VRM), which is found in most motherboards. This device provides power to the processor (typically through pins on the processor socket) and self-calibrates to supply the correct voltage to the processor. The VRM is designed to be powered from both +5 V and +12 V input voltage.

For many years, only +5 V was used, but since 2000, most VRMs have switched to +12 V due to the lower requirements for handling this input voltage. In addition, other PC components can also use the +5 V voltage supplied through the common pin on the motherboard socket, while only disk drives are "hung" on the +12 V line (at least, this was the case before 2000).

Whether the VRM on your board uses + 5V or + 12V depends on the specific board model and voltage regulator design. Many modern VRMs are designed to accept input voltages from +4 V to +26 V, so the final configuration is determined by the motherboard manufacturer.

For example, somehow we got our hands on a FIC (First International Computer) SD-11 motherboard equipped with a Semtech SC1144ABCSW voltage regulator.

This board uses +5 V, converting it to a lower voltage according to the needs of the CPU. Most motherboards use VRMs from two manufacturers - Semtech or Linear Technology. You can visit the websites of these companies and study the specifications of their chips in more detail.

The motherboard in question used an Athlon 1 GHz Model 2 processor in a slotted version (Slot A) and was specced to require 65W at 1.8V nominal. 65W at 1.8V corresponds to 36 , A.

When using a VRM with an input voltage of +5 V, a power of 65 W corresponds to a current strength of only 13 A. But this arrangement is obtained only if the voltage regulator is 100% efficient, which is impossible. Typically, the VRM efficiency is about 80%, so for the processor to work together with the voltage regulator, the current should be approximately equal to 16.25 A.

When you consider that other power consumers on the motherboard also use the +5 V line - remember that ISA or PCI cards also use this voltage - you can see how easy it is to overload the +5 V lines on the PSU.

While most motherboard VRM designs are inherited from Pentium III and Athlon / Duron processors that use + 5V regulators, most modern systems use VRMs rated for + 12V. This is because higher voltages reduce current levels. We can verify this with the example AMD Athlon 1 GHz already mentioned above:

As you can see, using the + 12V line to power the chip requires a current of only 5.4A or 6.8A, taking into account the efficiency of the VRM.

So we could reap a lot of benefits by connecting the VRM on the motherboard to the + 12V power line. But, as you already know, the ATX 2.03 specification assumes only one + 12V line, which is sent through the main power cable of the motherboard.

Even the short-lived auxiliary 6-pin connector was devoid of contact with the + 12V voltage, so it could not help us. A current of more than 8 A through a single 18-gauge wire from the +12 V line on the power supply is a very effective way to melt the ATX connector pins, which, according to the specification, are rated for a current no higher than 6 A using standard Molex pins. Thus, a fundamentally different solution was required.

Platform Compatibility Guide (PCG)

The processor directly controls the current through the + 12V pin. Modern motherboards are designed to support as many processors as possible, however, some motherboards' VRM circuits may not provide enough power for all processors that may be installed in a socket. on the motherboard.

To eliminate potential compatibility issues that could lead to PC instability or even component failure, Intel has developed a power standard called the Platform Compatibility Guide (PCG).

PCG is featured on most Intel boxed processors and motherboards from 2004 to 2009. It was created for PC builders and system integrators to inform them about the power requirements of the processor, and whether the motherboard meets these requirements.

PCG is a two-digit or three-digit designation (for example, 05A), where the first two digits represent the year the product was introduced, and an additional third letter corresponds to the market segment.

PCG markings, including the third character A, correspond to low-end processors and motherboards (require less power), while the letter B refers to processors and motherboards related to the high-end market segment (require more power ).

Motherboards that support high-end processors, by default, can also work with less powerful processors, but not vice versa.

For example, you can install a 05A-marked PCG processor into a 05B-marked motherboard, but if you try to install a 05B processor into a 05A-marked PCG, you may well face system instability or other, more serious consequences.

In other words, it is always possible to install a less efficient processor in an expensive motherboard, but not vice versa.

4-pin + 12V processor power connector

To increase the current on the + 12V line, Intel created a new ATX12V PSU specification. This led to the emergence of a third power connector called ATX + 12V and was used to supply an additional + 12V voltage to the motherboard.

This 4-pin power connector is standard on all ATX12V motherboards and contains Molex Mini-Fit Jr. pins. with female plugs. According to the specification, the connector complies with the Molex 39-01-2040 standard, the connector type is Molex 5556. This is the same type of pins used in the main power connector of the ATX motherboard.

This connector has two +12 V contacts, each of which is rated for a current of up to 8 A (or up to 11 A when using HCS contacts). This provides a current of 16 A in addition to the contact on the motherboard, and in total both connectors provide a current of up to 22 A on the +12 V line. The pin arrangement of this connector is shown in the following diagram:

Using standard Molex contacts, each pin in the + 12V connector can conduct up to 8A, 11A with HCS contacts, or 12A with Plus HCS contacts. Even though this connector uses the same pins as the main one, the current through this connector can reach higher values since fewer pins are used. By multiplying the number of contacts by the voltage, you can determine the maximum current power for this connector:

Molex standard contacts are rated for 8 A.

Molex HCS contacts are rated for 11 A.

Molex Plus HCS contacts are rated for 12 A.

All values are for a Mini-Fit Jr. 4-6 pin bundle. when using 18 gauge wires and standard temperature.

Thus, in the case of using standard contacts, the power can reach 192 W, which, in most cases, is sufficient even for modern high-performance CPUs. Consumption of more power can lead to overheating and melting of the contacts, therefore, in the case of using more "gluttonous" processor models, the + 12V plug to power the processor must include the Molex HCS or Plus HCS contacts.

The 20-pin main power connector and the + 12V processor power connector together provide a maximum current of 443W (using standard pins). It is important to note that the addition of a + 12V connector allows the full power of the 500W PSU to be used without the risk of overheating or melting the contacts.

Adapter for +12 V processor power connector

If the power supply does not have a standard + 12V connector for powering the processor, and the motherboard has a corresponding socket, there is a simple way out of the problem - use an adapter. What nuances can we face in this case?

The adapter connects to the connector for peripheral devices, which is available in almost all power supplies. The problem in this case is that the peripheral connector has only one + 12V pin, and the 4-pin CPU power connector has two such pins.

Thus, if the adapter assumes the use of only one connector for peripheral devices, using it to provide voltage on two pins of the +12 V connector for the processor at once, then in this case we see a serious discrepancy between the requirements for current strength.

Since the pins on the peripheral connector are rated for only 11 amps, a load exceeding this value could overheat and melt the pins on that connector. But 11 A is below the current peak values that the connector pins should be rated for in accordance with the Intel PCG recommendations. This means that these adapters do not comply with the latest standards.

We made the following calculations: given a VRM efficiency of 80%, for an average by today's standards processor consuming 105 W, the current level will be approximately 11 A, which is the maximum for the peripheral power connector.

Many modern processors have a TDP over 105 W. But we would not recommend using adapters that use only one connector for peripherals with processors with a TDP of over 75W. An example of such an adapter is shown in the following figure:

8-pin +12 V processor power connector

High-end motherboards often use multiple VRMs to power the processor. To distribute the load between additional voltage regulators, these boards are equipped with two 4-pin + 12V connectors, but they are physically combined into one 8-pin connector, as shown in the figure below.

This type of connector was first introduced in the EPS12V specification version 1.6, released in 2000. Although this specification was originally targeted at file servers, the increased power demands of some high-end desktop processors have led to the introduction of this 8-pin connector into the PC world.

Some motherboards that use an 8-pin CPU power connector must receive voltage across all pins of the connector to work correctly, while most motherboards of this type can work even if you only use one 4-pin power connector. In the latter case, there will be four free contacts on the motherboard socket.

But before starting a computer with such a configuration of connectors, you need to read the motherboard user's manual - most likely, it will reflect whether it is possible to connect one 4-pin power connector to an 8-pin socket on the board, or not.

If you are using a processor that draws more power than a single 4-pin power connector can supply, you will still need to find a PSU equipped with an 8-pin connector.

Adapter 4-pin -> 8-pin CPU + 12V power connector

If the motherboard requires voltage on all eight pins, but at the same time you are using a not too "gluttonous" processor and your power supply does not have an 8-pin connector, then an adapter from a 4-pin to an 8-pin connector can come to the rescue. It looks like this:

There are adapters that work in the opposite direction - that is, they convert the signal from an 8-pin connector to a 4-pin one.

But they are rarely needed, as you can do it easier by plugging an 8-pin connector into four sockets on the motherboard.

To do this, you just need to move the connector to one side. An adapter is indispensable if the physical layout of the board does not allow for an offset 8-pin connector.

Methodology and stand

In today's testing, a large amount of computer hardware was used to show how much power real-life gaming systems consume. In this regard, I relied on assemblies of the "Computer of the month" section. A complete list of all components is shown in the table below.

Test bench, software and auxiliary equipment
CPU	Intel Core i9-9900K Intel Core i7-9700K Intel Core i5-9600K Intel Core i5-9500F AMD Ryzen 5 1600 AMD Ryzen 5 2600X AMD Ryzen 7 2700X
Cooling	NZXT KRAKEN X62
Motherboard	ASUS ROG MAXIMUS XI FORMULA ASUS ROG Crosshair VIII Formula ASUS ROG STRIX B450-I GAMING
RAM	G.Skill Trident Z F4-3200C14D-32GTZ, DDR4-3200, 32 GB Samsung M378A1G43EB-CRC, DDR4-2400, 16 GB
Video card	2 × ASUS ROG Strix GeForce RTX 2080 Ti OC ASUS Radeon VII ASUS DUAL-RTX2070-O8G NVIDIA GeForce RTX 2060 Founders Edition ASUS ROG-STRIX-RX570-4G-GAMING AMD Radeon RX Vega 64 ASUS PH-GTX1660-6G
Storage device	Samsung 970 PRO MZ-V7P1T0BW
Power Supply	Corsair CX450 Corsair CX650 Corsair TX650M Corsair RM850x Corsair AX1000
Frame	Open test bench
Monitor	NEC EA244UHD
Operating system	Windows 10 Pro x64 1903
Software for video cards
NVIDIA	431.60
AMD	19.07.2005
Additional software
Removing drivers	Display Driver Uninstaller 17.0.6.1
FPS measurement	Fraps 3.5.99
	FRAFS Bench Viewer
	Action! 2.8.2
Overclocking and monitoring	GPU-Z 1.19.0
Overclocking and monitoring	MSI Afterburner 4.6.0
Optional equipment
Thermal imager	Fluke Ti400
Sound level meter	Mastech MS6708
Wattmeter	watts up? PRO

Test benches were loaded with the following software:

Prime95 29.8- Small FFT test, which maximizes the load on the central processor. This is a very resource-intensive application, in most cases, programs that use all cores are not able to load the chips more.
AdobePremierPro 2019- rendering of 4K video by means of the central processor. An example of resource-intensive software that uses all processor cores, as well as available reserves random access memory and storage.
"The Witcher 3: Wild Hunt"- tested in full screen at 4K resolution using maximum settings quality graphics. This game puts a heavy load on not only the video card (even two RTX 2080 Ti in the SLI array are 95% loaded), but also the central processor. Eventually system unit loads more than, for example, using FurMark "synthetics".
"The Witcher 3: Wild Hunt" +Prime95 29.8(Small FFT test) - a test for the maximum power consumption of the system when both the CPU and GPU are loaded at 100%. And yet, it should not be ruled out that there are more resource-intensive bundles.

Energy consumption was measured using a watts up? PRO - despite such a comical name, the device can be connected to a computer, and using special software, it allows you to monitor its various parameters. So, the graphs below will show the average and maximum power consumption levels of the entire system.

The period of each power measurement was 10 minutes.

⇡ What power is needed for a modern gaming PC

I will note again: this article is to a certain extent tied to the "Computer of the Month" section. Therefore, if you have dropped by to see us for the first time, then I recommend that you familiarize yourself with at least. In each "Computer of the Month" six assemblies are considered - mostly game ones. I used similar systems for this article. Let's get acquainted:

A bundle of Ryzen 5 1600 + Radeon RX 570 + 16 GB of RAM is an analogue of the starting assembly (35,000-37,000 rubles for a system unit, excluding the cost of software).
A bundle of Ryzen 5 2600X + GeForce GTX 1660 + 16 GB of RAM is an analogue of the basic assembly (50,000-55,000 rubles).
A bundle of Core i5-9500F + GeForce RTX 2060 + 16 GB of RAM is an analogue of the optimal assembly (70,000-75,000 rubles).
A bundle of Core i5-9600K + GeForce RTX 2060 + 16 GB of RAM is another option for the optimal assembly.
A bundle of Ryzen 7 2700X + GeForce RTX 2070 + 16 GB of RAM is an analogue of an advanced assembly (100,000 rubles).
A bundle of Ryzen 7 2700X + Radeon VII + 32 GB of RAM is an analogue of the maximum assembly (130,000-140,000 rubles).
A bundle of Core i7-9700K + Radeon VII + 32 GB of RAM is another option for the maximum build.
A bundle of Core i9-9900K + GeForce RTX 2080 Ti + 32 GB of RAM is an analogue of an extreme assembly (220,000-235,000 rubles).

Unfortunately, I could not get the Ryzen 3000 processors at the time of all the tests, but the results obtained from this will not become less useful. The same Ryzen 9 3900X, consumes less Core i9-9900K - it turns out that in the framework of an extreme assembly, it will be even more interesting and important to study the power consumption of an 8-core Intel.

And also, as you may have noticed, the article uses only mainstream platforms, namely AMD AM4 and Intel LGA1151-v2. I did not use HEDT systems like TR4 and LGA2066. First, we have long since abandoned them in Computer of the Month. Secondly, with the appearance in the mass segment of the 12-core Ryzen 9 3900X and in anticipation of the imminent release of the 16-core Ryzen 9 3950X, such systems have become painfully highly specialized. Thirdly, because the Core i9-9900K still gives everyone a light in terms of energy consumption, once again proving that the calculated thermal power declared by the manufacturer says little to the consumer.

Now let's move on to the test results.

To be honest, the test results in programs such as Prime95 and Adobe Premier Pro 2019, I cite more for your information - for those who do not play and do not use discrete graphics cards... You can safely focus on this data. Basically, here we are interested in the behavior of test systems in loads close to maximum.

And here are very interesting things. In general, we see that all considered systems do not consume very much energy. The most voracious, which is quite logical, was the system with Core i9-9900K and GeForce RTX 2080 Ti, but even in stock (read - without overclocking) consumes 338 W when it comes to games, and 468 W - at maximum PC load. It turns out that such a system will have enough power supply for an honest 500 watts. It is so?

⇡ It's not just about watts

It would seem that this is the end of the article: recommend everyone a power supply with a capacity of 500 honest watts - and live in peace. However, let's do some additional experimentation to get a complete picture of what's going on with your PC.

In the screenshot above, we see that the power supplies work as efficiently as possible at 50% load, that is, half of the declared power. It may seem to someone that the difference between a device with a basic 80 PLUS certification with an efficiency at peak of about 85% in a 230 V network and, say, a "platinum" PSU with an efficiency of about 94% is not so great, but this is a delusion. my colleague Dmitry Vasiliev points out quite accurately: “A source of energy with an efficiency of 85% uselessly spends 15% of its power on heating the ambient air, while only 6% of the power is converted into heat by the“ breadwinner ”with an efficiency of 94%. It turns out that the difference is not “ some there"10%, but x2.5". Obviously, in such conditions, a more efficient power supply unit runs quieter (it makes no sense for the manufacturer to adjust the fan of the device to the maximum speed), and it heats up less.

And here is the proof of the above words.

The graphs above show the efficiency of some power supplies participating in the tests, as well as the rotational speed of their fans at different degrees of load. Unfortunately, the equipment used does not allow us to accurately measure the noise level, but by the number of revolutions per minute of the built-in fans, we can judge how noisy the power supply will be. It should be noted here that this does not mean at all that under load the power supply unit will stand out “from the crowd”. Yet usually the noisiest components gaming computer are cpu cooler and a video card.

Practice, as you can see, converges with theory. The power supplies do operate at their maximum efficiency at about 50 percent load. Moreover, in this regard, I would like to note the Corsair AX1000 model - this power supply reaches its peak efficiency with a power of 300 W, and then its efficiency does not fall below 92%. But other Corsair blocks on the charts have the expected "hump".

At the same time, the Corsair AX1000 can operate in a semi-passive mode. Only at a load of 400 W does its fan start spinning at a frequency of ~ 750 rpm. The RM850x has the same characteristic, but in it the impeller starts to rotate at a power of ~ 200 W.

Now let's take a look at the temperatures. To do this, I disassembled all the power supplies. The fans from the top cover were removed and installed on a homemade tripod so that the distance between it and the rest of the PSU was about 10 cm. I'm sure the device did not work worse in terms of cooling, but this design allowed me to take pictures with a thermal imager. In the graph above, "Temperature 1" refers to the maximum temperature of the power supply inside when the fan is running. "Temperature 2" is the maximum heating of the PSU ... without additional cooling. Please do not repeat such experiments at home on your equipment! However, such a bold move allows you to clearly show how the power supply heats up and how its temperature depends on the rated power, build quality and the used component base.

Heating the CX450 to 117 degrees Celsius is quite a logical phenomenon, because this power supply operates at a load of 400 W at almost maximum, and even does not cool down in any way. The fact that the power supply has passed this test at all is an excellent sign. Here is a high-quality budget model.

Comparing the results of other power supplies, one can come to the conclusion that they seem quite logical: yes, the Corsair CX450 model heats the most, and the RM850x least of all. At the same time, the difference in the maximum heating rates is 42 degrees Celsius.

It is important here to define the concept of “honest power”. Here is a Corsair CX450 model on a 12-volt line can transfer 449 watts of power. It is this parameter that must be looked at when choosing a device, because there are models that do not work as efficiently. In cheaper units of similar power, noticeably fewer watts can be transmitted over a 12-volt line. It comes to the point that the manufacturer claims support for 450 watts, but in fact it is only about 320-360 watts. So let's write it down: when choosing a power supply, you need to look, among other things, at how many watts the device produces over a 12-volt line.

Let's compare the Corsair TX650M and CX650, which have the same power rating but are certified to different 80PLUS gold and bronze standards respectively. I think the images of the thermal imager attached above speak more eloquently than any words. Really, support for a specific standard 80PLUS indirectly speaks about the quality of the element base of the power supply... The higher the certificate class, the better block nutrition.

It is important to note here that the Corsair TX650M transmits up to 612 watts over the 12-volt line, and the CX650 up to 648 watts.

Above in the pictures you can compare the heating of the RM850x and AX1000 models, but already at a load of 600 watts. Here, too, there is an obvious difference in temperatures. Overall, we can see that Corsair PSUs do a good job of handling the load they put on them - and even in stressful situations. At the same time, I think it is now clear why the above graph did not show the temperature of the AX1000 - it does not get too hot, even if you remove the cover with the fan from it.

Considering the results obtained, you can see that it is completely unreasonable to use a power supply in the system with a power twice the maximum power of the PC itself. In this operating mode, the power supply unit heats up less and makes noise - these are facts that we have just proved once again. It turns out that a PSU with an honest power of 450 W is suitable for a starting assembly, for a basic one - 500 W, for an optimal one - 500 W, for an advanced one - 600 W, for a maximum one - 800 W, and for an extreme one - 1000 W. Plus, in the first part of the article, we found out that there is not such a big difference in price between power supplies, the declared power of which differs by 100-200 watts.

However, let's not rush to final conclusions.

⇡ A few words about the upgrade

The assemblies in "Computer of the Month" are designed not only to work in the default mode. In each issue, I talk about the overclocking capabilities of some components (or the pointlessness of overclocking in the case of some processors, memory and video cards), as well as the possibilities of the subsequent upgrade. There is an axiom: the cheaper the system unit, the more compromises it has... Compromises that will allow you to use a PC here and now, but the desire to get something more productive, quiet, efficient, beautiful or comfortable (necessary - emphasize) will not leave you anyway. Captain Evidence suggests that in such situations, a power supply unit with a good margin of watts is very useful.

Let me give you an illustrative example of an upgrade of a starter assembly.

I took the AM4 platform. 6-core Ryzen 5 1600, Radeon RX 570 and 16GB DDR4-3000 RAM were recommended. Even with a stock cooler (a cooling system that comes with the CPU), our chip can be easily overclocked to 3.8 GHz. Let's say I took a radical step and changed the CO for a much more efficient model, which allowed me to raise the frequency from 3.3 to 4.0 GHz while loading all six cores. To do this, I needed to raise the voltage to 1.39 V, and also set the fourth Load-Line Calibration level of the motherboard. This overclocking essentially turned my Ryzen 5 1600 into a Ryzen 5 2600X.

Let's say I bought a Radeon RX Vega 64 video card - on the Computeruniverse website a month ago it could be taken for 17,000 rubles (excluding shipping), and even cheaper from hands. And in the comments to "Computer of the Month" they talk so sweetly about used GeForce GTX 1080 Ti, sold for 25-30 thousand rubles ...

Finally, instead of the Ryzen 5 1600, you can take the Ryzen 2700X, which has dropped significantly in price after the release of the third-generation AMD family of chips. There is no particular need to disperse it. As a result, we see that in both cases of the upgrade I proposed, the power consumption of the system has more than doubled!

This is just an example, and the characters in the described situation may be completely different. However, this example, in my opinion, clearly shows that even in the starting assembly, a power supply with an honest power of 500 W, and even better 600 W, does not interfere at all.

⇡ Overclocking and everything connected with it

Speaking of overclocking, I will give an example of the power consumption of the stands before and after overclocking. The frequencies have been increased for the following systems:

Ryzen 5 1600 (@ 4.0 GHz, 1.39 V, LLC 4) + Radeon RX 570 (1457/2000 MHz) + 16GB RAM (DDR4-3200, 1.35 V).
Ryzen 5 2600X (@ 4.3 GHz, 1.4 V, LLC 4) + GeForce GTX 1660 (1670/2375 MHz) + 16GB RAM (DDR4-3200, 1.35 V).
Core i5-9600K (@ 4.8 / 5.0 GHz, 1.3 V, LLC 4) + GeForce RTX 2060 (1530/2000 MHz) + 16 GB RAM (DDR4-3200, 1.35 V).
Ryzen 7 2700X (@ 4.3 GHz, 1.4 V, LLC 4) + GeForce RTX 2070 (1500/2000 MHz) + 16 GB RAM (DDR4-3200, 1.35 V).
Ryzen 7 2700X (@ 4.3 GHz, 1.4V, LLC 4) + Radeon VII (2000/1200 MHz) + 32GB RAM (DDR4-3400, 1.4V).
Core i7-9700K (@ 5.0 / 5.2 GHz, 1.35 V, LLC 5) + Radeon VII (2000/1200 MHz) + 32 GB RAM (DDR4-3400, 1.4 V).
Core i9-9900K (@ 5.0 / 5.2 GHz, 1.345 V, LLC 5) + GeForce RTX 2080 Ti (1470/1980 MHz) + 32 GB RAM (DDR4-3400, 1.4 V).

"Gaming PCs do not need 1 kW units" - commentators under the articles on the site

Comments like this are often seen when it comes to gaming PCs. In the vast majority of cases - and we found it out in practice - this is how it is. However, in 2019 there is a system that is able to impress with its power consumption.

We are talking, of course, about an extreme assembly in its, so to speak, maximum combat form. Not so long ago, an article "" was published on our site - in it we talked in detail about the performance of a pair of the fastest GeForce video cards in 4K and 8K resolutions. The system is fast, but the components are selected in such a way that it is very easy to make it even faster. In addition, it turned out that overclocking the Core i9-9900K to 5.2 GHz turns out to be completely useful in the case of the GeForce RTX 2080 Ti SLI array and Ultra HD games. Only at its peak, as we can see, such an overclocked configuration consumes more than 800 watts. Therefore, for such a system in such conditions, a kilowatt power supply will definitely not be superfluous.

⇡ Conclusions

If you have carefully read the article, then you have identified for yourself several main points that you need to keep in mind when choosing a power supply. Let's list them all again:

unfortunately, it is impossible to rely on the TDP indicators declared by the manufacturer of the video card or processor;
the power consumption of computer equipment does not change much from year to year and is within certain limits - therefore, a high-quality power supply unit purchased now will last a long time and will serve faithfully and will definitely come in handy during the assembly of the next system;
the needs for cable management of the system unit also affect the choice of a power supply unit of a certain power;
not all power connectors on the motherboard need to be used;
the power supply unit of lower power is not always more profitable (in terms of price) than a more powerful model;
when choosing a power supply, one must look, among other things, at how many watts the device produces over a 12-volt line;
support for a certain standard 80 PLUS indirectly speaks of the quality of the element base of the power supply;
it is completely unjustifiable to use a power supply whose honest power is twice (or even more) the maximum power consumption of the computer.

Quite often you can hear the phrase: “ More is not less". This very laconic aphorism perfectly describes the situation when choosing a power supply. Take a model with a good power reserve for your new PC - it will definitely not be worse, but in most cases it will only be better. Even for an inexpensive gaming system unit, which consumes about 220-250 W at maximum load, it still makes sense to take a good model with an honest 600-650 W. Because a block like this:

will work quieter, and in the case of some models - absolutely silent;
it will be colder;
will be more efficient;
will allow you to easily overclock the system, increasing the performance of the central processor, video card and RAM;
will allow you to easily upgrade the main components of the system;
will survive several upgrades, and also (if the power supply is really good) will settle in the second or third system unit;
will also allow you to save money during the subsequent assembly of the system unit.

I think very few readers will refuse a good power supply. It is clear that it is not always possible to immediately buy a high-quality device with a large reserve for the future. Sometimes when buying a new system unit and a limited budget, you want to take a more powerful processor, and faster video cards, and a higher-capacity SSD - all this is understandable. But if you have the opportunity to buy a good power supply with a margin, you do not need to save on it.

We express our gratitude to the companiesASUS andCorsair as well computer store"Regard" for the equipment provided for testing.

#Lines_number_ + 12V

You can independently identify how many lines in a particular power supply unit can be by its label - if there are more than one lines, then the maximum load in amperes is separately indicated for each + 12V circuit, which are designated as "+ 12V1, + 12V2, etc.". The actual output lines are called "rails" in English, and, accordingly, a power supply unit with one output line will be called "single rail PSU", and with several - "multiple rails PSU".

PSU with one line + 12V

PSU with multiple lines + 12V

There are several models of power supplies that actually have two voltage sources + 12V, but these are usually very high power supplies (from 1000W). And in most cases, these two exits are again divided into four, five or six lines for security reasons. (But, for example, u do not share, and this is not so bad, which will be discussed further)

In some even rarer cases, the two original + 12V lines can be combined into one powerful output.

So why do you really need to separate the + 12V lines?

Security. For the same reason, houses, as a rule, have more than one fuse-switch (popularly known as "packet bags"). The ultimate goal is to limit the current in one circuit to 20A so that the temperature of the conductor carrying it does not become dangerous.

Short-circuit protection is triggered only when there is almost complete absence of resistance in the short-circuited circuit (that is, for example, when a bare wire hits "ground"), and in more difficult cases, when a short circuit occurs on a printed circuit board or in an electric motor, resistance in the circuit remains sufficient to prevent short-circuit protection from tripping. In this case, a very large load on the circuit arises and a rapid increase in the current strength in the conductors leads, first of all, to the melting of the insulation and subsequently to a fire. Limiting the current on each line removes this problem, i.e. that is why it is necessary to divide the outputs into separate lines with individual stops.

Is it true that in some power supplies with the declared multiple + 12V lines, there is no line separation at all?

Yes it is. Fortunately, this is the exception to the rule, not the norm. This is done to reduce development and production costs. Why is it stated that there are several lines - in order to fully comply with the ATX12V specification, because in other characteristics it is observed.

Why do such power supplies remain on the market, and manufacturers have no problems with their certification?

Yes, because Intel recently removed the + 12V line splitting requirement from the specification, but has not publicly announced this fact. They just changed "required" to "recommended", leaving the manufacturers a little puzzled.

Does splitting the + 12V lines give "cleaner and more stable voltages"?

The truth is that marketers constantly emphasize this fact, but usually it is not, it just sounds more euphonious than "This PSU is unlikely to cause a fire." And since, as already mentioned above, all lines in most cases originate from one source, and no additional filtering is performed, the voltages remain the same even if there were no divisions.

Why do some people presume that a PSU with a single + 12V output is better?(just a great example -)

There were a few companies that made PSUs with four 12V lines that, in theory, were supposed to supply more than enough current for a high-end gaming station and ran into a lot of problems. Making the PSU in accordance with the EPS12V server specification, all PCI-E 6-pin connectors were removed from the common + 12V lines with a load capacity of 18A, instead of a separate one. This line was easily overloaded by two powerful graphics cards along with other possible consumers, resulting in a PC shutdown. Instead of a "civilized" solution to the problem, these manufacturers have given up on dividing + 12V outputs altogether.

Now PSUs "for enthusiasts" with several + 12V lines have either an overestimated maximum load capacity of the line intended for PCI-E connectors (and nothing else is connected to it), or two such lines are distributed over four or even six connectors. And PS certification for SLI in any case requires at least a separate + 12V line for PCI-E connectors.

To make a PSU with split lines costs 1.5 - 3 US dollars more for the manufacturer, and in most cases this amount is not passed on to the buyer, which already forces marketers to put forward theories that PSUs with no splitting + 12V lines are no worse or even better. ...

But nevertheless, there are statements that, for example, power supplies with one + 12V line are better suited for overclocking, etc. But this is more like a placebo effect, which arose due to the fact that, for example, their previous PSU was faulty, was not powerful enough, or the load was not properly distributed along the lines.

So it turns out that a power supply unit with + 12V load distribution over several lines does not have any specific drawbacks?

No, actually, it is not. Let's look at two examples:

Example # 1:

One model of power supply unit rated at 700W formally has enough power for any SLI system of two single-chip video cards. But this PSU has only two PCI-E connectors, each of which hangs on its own + 12V line. The problem is that these lines are capable of delivering 18 amps, which is almost three times the maximum current that the 6-pin PCI-E graphics card connector can handle. Accordingly, when you try to install two video cards that require two of these connectors, problems begin.

It would be ideal if two connectors were soldered to each of the lines, but instead you have to use adapters from the "regular" 4-pin Molex to PCI-E 6-pin, which leads to an overload of the circuits from which the rest of the system is powered. block, while the actual "video card" circuits remain heavily underloaded. The problem could be solved by a 6-pin PCI-E -> 2x 6-pin PCI-E adapter in two copies, but it cannot be called widespread. So in a situation like this, the most the best solution problems (in addition to replacing the power supply unit), there remains an independent soldering of two PCI-E connectors to two corresponding lines.

Example # 2:

Thermo-electric coolers (also called Peltier coolers) consume a lot of power and are usually powered by Molex connectors. Some models generally use their own separate power supply unit.

So, if you use a power supply unit with line separation and powered your Peltier element from one of the molecules, then it turns out to be on the same line with accumulators, fans, etc., then this line may also be overloaded, since it is transplanted to other lines, designed to power video cards is impossible without significant tweaks. Naturally, a power supply unit with one + 12V line would be devoid of any problems in such a situation.

Typical configurations for multiple + 12V lines:

2 x 12V lines, example -
This is the original ATX12V specification for dividing + 12V lines. One is for the processor, the other is for everything else. It is very unlikely that a modern high-end video card with high power consumption will fit into the "everything else". Such a division could only be seen on a power supply unit with a power less than 600W.
3 x 12V lines, example -
Modifications to the ATX12V specification, taking into account the use of PCI-E connectors for powering video cards. One lane per processor, one for PCI-E connectors and one for everything else. Works great even with some SLI configurations, but not recommended for two video cards that require four PCI-E connectors in total.
4 x 12V lines (EPS12V), example -
In the original, this configuration was required by the EPS12V specification. Since typical applications of such PSUs imply their use in dual-processor systems, the two + 12V lines are intended exclusively for powering the processors via 8-pin connectors. Everything else, including drives and video cards, falls on the two remaining lines. Currently, nVidia does not certify such PSUs for SLI, since there is no separate + 12V line for video cards in such PSUs. In the segment of PSUs that are not intended for servers, there will no longer be such PSUs; several 700-850W models made according to such an architecture for the gaming PC market have already been discontinued.
4 x 12V lines (The most popular layout in the "PC for enthusiasts" segment), example -
"Upgraded" ATX12V, similar to 3 x 12V, apart from the fact that two to six PCI-E connectors are split between two additional + 12V lines. Such a scheme is most often found in a power supply unit with a power from 700 to 1000 watts, although at a power of 800 watts or more, some of the lines may have much more than 20 amperes, which is not quite standard, but it seems to have already become a common practice, for example -
5 x 12V lines, for example -
These PSUs can be called a hybrid EPS12V / ATX12V. Two processors with their own power lines, also two lines go to PCI-E connectors. The power of such PSUs usually ranges from 850 to 1000 watts.
6 x 12V lines, example -
Most attractive and universal option, since, in accordance with the EPS12V specification, it can have four to six PCI-E connectors without exceeding the current of 20A on any of the lines (although in practice this limitation, as you have already seen, is interpreted rather loosely). Two lines go to processors, two to video cards, two to everything else. This configuration can be seen in a power supply unit with a capacity of 1000 watts or more.

As a conclusion, we can note the fact that 99% of users will never think about whether their power supply has a common or separate + 12V lines. Perhaps marketers will continue to extol the merits of both options, but the criteria for buying a PSU will still remain the same:

Sufficient power for the selected configuration.
Sufficient number of suitable connectors for the selected configuration.
SLI or CrossFire certified when using the appropriate MultiGPU configuration.