{"id":87962,"date":"2022-02-10T06:00:09","date_gmt":"2022-02-10T05:00:09","guid":{"rendered":"https:\/\/www.hwcooling.net\/?p=87962\/"},"modified":"2022-02-09T22:12:41","modified_gmt":"2022-02-09T21:12:41","slug":"nvidia-12pin-and-pcie-5-0-gpu-power-connector-interoperability","status":"publish","type":"post","link":"https:\/\/www.hwcooling.net\/en\/nvidia-12pin-and-pcie-5-0-gpu-power-connector-interoperability\/","title":{"rendered":"Nvidia 12pin, PCIe 5.0 GPU power connector and interoperability"},"content":{"rendered":"

In 2020, Nvidia introduced a new power connector<\/a> with GeForce RTX 3000 (Ampere) graphics. This originally seemed to be a proprietary Nvidia design that was only used by their own Founders Edition cards (and it required getting adapters\/new cables for most PSUs). But now it seems to be turning into a standardised power connector under PCI Express 5.0 – well, almost. The situation around these cables is a bit more complicated.<\/p>\n

The original power cable for the GeForce RTX 3000 “Founders Edition” has twelve wires\/pins. Last year, however, reports started surfacing that the new GeForce RTX 3090 Ti<\/a> (which pushes the TDP to an insane 450W) will have a new connector again, this time a 16-pin one<\/a>. However, it was supposed to be a standardized connector this time, which should be specified as part of the PCI Express 5.0 technology (although the GPU itself probably does not yet use Gen5 PCIe to connect to the system).<\/p>\n

Asus then revealed the first power supply to provide this PCI Express 5.0 cabling<\/a>, but the connector it uses is only 12pin. And it seems to be the same as the one featured in original Ampere\/RTX 3000 cards. So is it that they were designed so thoughtfully in advance and were PCI Express 5.0 ready from the start, or did Nvidia then have this power supply design incorporated into the upcoming standard? Yes and no.<\/p>\n

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12pin auxiliary power connector for GeForce RTX 3000 graphics (Source: HardwareLuxx)<\/figcaption><\/figure>\n

Twelve-pin versus 12VHPWR connector<\/h3>\n

According to current information, the 12-pin power supply for Founders Edition graphics (even those from 2020, not just the new RTX 3090 Ti) is compatible with the new PCI Express 5.0 standard. The connectors physically fit and the new power supplies will be able to power these graphics cards directly. However, it could become a bit more complicated if you wanted to use current power supplies and 12pin adapters for future PCIe 5.0 graphics in the future with this power supply, as this compatibility is partial.<\/p>\n

Cables under the PCI Express 5.0 standard will be more complex. While Nvidia uses a 12-pin connector,PCI Express 5.0 does really specify a 16-pin connector. This connector has the same electrical wires and pins and physically matches the 12pin connector (it is a Molex MicroFit 3.0) used by Nvidia, and both should be interoperable – i.e. you can plug a 16pin into a card with a 12pin port. The 16pin connector – or perhaps better said 12+4pin – has an additional four wires and pins however. But these are data pins, they are used for simple communication between the PCI Express card and the power supply, not for supplying power.<\/p>\n

It seems that the difference between 12pin and 16pin is that according to the PCI Express 5.0 standard, a 12-wire cable should cap the delivered current to a value that at 12V voltage will be equivalent to 450 W of power. However, if you use the full 16-wire cable and the card also has the appropriate contacts in the connector, it can negotiate a higher supply with the power supply using the data wires, and thanks to this the 16-pin connector can provide up to 600 W of power. Separately, at 12V voltage, the connector\/cable is supposed to limit the maximum current passing through to 9 A, which would give 648 W, but the lower maximum of 600 W probably applies to the power draw.<\/p>\n

No complicated communication protocol is used, basically if pin “S3” (SENSE0) is connected and grounded via the card, the power supply sends 600 W; if the wire is missing (this grounding is not present), the power supply should limit the output to 450 W. The other two pins provide additional signalling (CARD_PWR_STABLE, CARD_CBL_PRES#), this should probably be a feedback to the PSU that the power supply is OK and that the card is correctly present and installed. This complete 12+4pin version is labelled 12VHPWR High Power Connector (H+)<\/b> according to PCIe 5.0 specifications.<\/p>\n

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Function of additional pins on 12VHPWR High Power Connector (H+) (Source: igor’sLAB)<\/figcaption><\/figure>\n

Will PCs have connectors with 12 or 16 pins?<\/h3>\n

If you remember the Asus Thor series PSU, which was the first one to announce support for PCI Express 5.0 power supply, Asus stated that it would be able to deliver up to 600 W over the cable. But – according to the photos, its connectors are only 12-pin, so they should deliver only 450 W.<\/p>\n

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ASUS ROG Thor II 1000W PSU with a 12pin connector (Source: HardwareLuxx<\/a>)<\/figcaption><\/figure>\n

So for a while it was not clear whether the power supply ability would actually be limited by the 12pin as the spec says or not. In the end, it seems that this part really applies. Asus has actually now changed the specs on their website and is now promising just 450W over a single 12pin cable.<\/p>\n

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Change in specifications of ROG Thor PSU with 12pin connector (Source: VideoCardz)<\/figcaption><\/figure>\n

However, the future Loki series PSU will support 600W power delivery to GPUs. This power supply will be using the 16pin\/wire cables, which will have the smart data part and thus will officially support 600W power supply.<\/p>\n

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Asus ROG Loki PSU with 16-pin PCI Express 5.0 connector for GPU power (Source: VideoCardz)<\/figcaption><\/figure>\n

12pin connector might be enough in practice (mostly?)<\/h3>\n

This will probably be the official working of the PCI Express 5.0 standard, but it’s quite possible that powerful high-end PSUs will still tolerate it when you will overload the 12V branch to above 450W, even if the cabling is only 12-wire without the data wires. Then, for example, when overclocking, you would be able to feed even those 600 W into the card with a single 12-wire cable. It will be out of spec, but that is something that generally applies to all overclocking anyway.<\/p>\n

In any case, hopefully for most of us the difference between full 12+4pin\/wire cables and the simpler 12pin cables and connectors (which might be all that will be provided by cheaper PSUs) will not be super important. Hopefully excessive graphics cards going over 400-450W with their power draw will be more of a rarity than norm and such madness won’t spread too much.<\/p>\n

It’s unclear whether the GeForce RTX 3090 Ti, which is supposed to have a 450W TDP according to the leaked data (note that it can probably still draw up to 75W from the PCIe \u00d716 slot, so not all the power has to go through the cable), will actually use a 16\/12+4pin connector and cables instead of the simple 12pin, or if it will even require one.<\/p>\n

Sources: VideoCardz (1<\/a>, 2<\/a>, 3<\/a>), igor’sLAB<\/a><\/i><\/p>\n

English translation and edit by Jozef Dud\u00e1\u0161, original text by\u00a0Jan Ol\u0161an, editor for Cnews.cz<\/em><\/p>\n