At the beginning of March, Intel released the ATX 3.0 specification, which brings spectacular changes to the world of power supplies.
Typically, development in the IT world is extremely fast, but there are also some areas that operate on the “slow water washes the shore” principle. The world of power supplies is exactly like this, which is also excellently characterized by the fact that version 2.0 of the recommendation for them was published twenty years ago, and since then Intel has only smuggled in minor modifications here and there. Now version 3.0 has been completed: greater performance, better reliability and higher efficiency are required, but compatibility must be compromised.
Key: PCI Express 5
If one dives a little deeper into the ATX 3.0 specification, it is easy to get the feeling that it is all about performance. This is a baroque exaggeration, but it is a fact that the draft envisages video cards with a consumption of 600 watts and their power supply, which do not even exist today. How can all this be reconciled with today’s fashionable energy-saving approach? So that the standard not only provides for the power supply of the video cards, but also sets expectations regarding the efficiency under low load, as well as contains additional regulations related to efficient operation.
But let’s start the series with the power supply of the video cards. Including the 12VHPWR connector type, which is actually part of PCI Express 5.0. The ATX 3.0 specification is related to the fact that power supplies using the standard can support four performance levels based on Intel’s recommendation. The 12VHPWR has a new 12+4 pin structure, of which 12 pins are responsible for the power supply, and four pins are for communication between the GPU and the power supply – this means in practice that the video card always knows exactly how much power it can draw from the power supply. (It is interesting that, according to the PCIe 5 standard, video cards must work even if the four-pin communication channel does not work for some reason, or if the power supply is only capable of lower performance than the GPU would need – of course, in such a case, with a lower clock signal and with lower performance.)
The connector with six pairs of wires can theoretically deliver a maximum power of 662.4 watts, the ATX 3.0 specification defines lower power levels of 600, 450, 300, and 150 watts – and the highest value must be indicated on the connector itself. It is also important that, according to the specification, this connector must only be used if the power supply has a total power of at least 450 watts – below that, it is only optional.
Efficiency and safety
Let’s see how efficiently the power supplies must work. At a load of at least 10 watts or 2 percent, the expected efficiency is 60 percent and the recommended efficiency is 70 percent. Manufacturers can use the Cybenetics certification instead of/in addition to the 80 Plus mark.
According to the specification, for example, the power supply and the motherboard can communicate with each other, so the motherboard can always communicate its current performance and load level to the power supply – if this is too high, the motherboard can decide to temporarily reduce the performance of the processor and/or GPU due to the overload. and even about the emergency shutdown of the PC. The output voltage limit has also changed for the +12 volt branch, which must provide a minimum of 11.2 and a maximum of 12.2 volts (previously 11.8 and 12.4 V were the limits) to the motherboard, while -8 to the GPU and +5 percent. The 5 volt and 3.3 volt limits have not changed, the maximum 5 percent difference “up” and “down” remained here (which means 4.75-5.25 and 3.135-3.465 V intervals).
At the same time as ATX 3.0, Intel also released the ATX12VO 2.0 specification. This would standardize the solutions that major computer manufacturers (e.g. Dell, HP) have been using for a long time: the power supply only produces 12 volts, and the motherboard takes care of the 5 and 3.3 volts. The question is how much this will spread – probably not at all in the short term.
From the new PCIe 5.0 connector – including the extra four communication channels – Intel also hopes that PCs will be able to overcome consumption anomalies much more smoothly. Currently, it is recommended to oversize power supplies by 30-40 percent so that high-voltage spikes occasionally produced by GPUs do not cause problems. However, according to the ATX 3.0 specification, extra capacitors must be included in the design to “manage” such spikes, namely in such a way that the power stored in the buffer can provide two or three times the nominal power consumption of the GPU for a short period of time (up to 0.1 seconds). Although this may not seem like much, this amount of “outages” can be enough to make a PC’s operation unstable. As for the overall performance, the power supplies must be able to withstand 120, 160, and 180 percent overloads for 100, 10, and 1 ms.
The monsters are coming!
Based on Intel’s estimates, even 1200 watts of power may be required for the most extreme demands at home. Although there are no GPUs that consume 600 watts yet, Intel expects manufacturers to reach this limit in the foreseeable future. In addition to this, Intel calculates the 300-watt consumption of an extreme processor, as well as another 300 watts of the motherboard and other hardware, resulting in a maximum power of 1200 watts. Of course, only a very few people will need this.
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