Considerations When Using a 12VHPWR Adapter

Working on the main system connectivity features, including PCIe, PCI-SIG has introduced a new standard in 2021 to catch up with the power consumption of high-performance graphics cards: the 12VHPWR connector, also known as PCIe 5.0 connection.

We will see the 12VHPWR replace some 8 pin molex connectors in next generation power supplies. As you know, as the power consumption increases, the number of 8 pin connectors used also increases. The 12VHPWR can deliver up to 600W over 12 channels, four times more than an 8-pin port. The dimensions of this connector are quite small.

PCI-SIG actually sees no problem with the 12VHPWR standard. However, the cheap 8-pin to 12VHPWR adapters that vendors have begun to bundle with some power supplies are starting to cause concern. PCI-SIG recently sent a message to consortium members expressing their concerns:

“ We would like to remind you that some applications of 12VHPWR connectors and assemblies exhibit thermal differences that can cause safety issues under certain conditions. Although PCI-SIG provides the necessary information for the common standard, appropriate standard design practices are not fully adopted in the industry. Because the PCI-SIG working groups include many knowledgeable experts in connector and systems design, they will review the available information on this industry problem and assist with any appropriate resolution.

We will provide further updates as PCI-SIG as new details emerge. In the meantime, we advise our members to work closely with their connector suppliers and exercise due care when using high-power connections, especially where there may be safety concerns. ”

An example is a 3×8 pin to 12VHWPR adapter.

PCI-SIG implicitly addresses the problems that can arise from poor quality connectors. In some cases, components can melt or even damage other hardware. Wccftech guesses the problem is due to the variability of 8 pin connectors. Most current generation GPUs require multiple 8-pin ports, and even then, connectors are often pushed to their nominal limits. The new generation GPUs, on the other hand, come with much higher power consumption as well as high performance.

12VHPWR Adapter Tests

In the quick test setup, a 12VHPWR connection was made with two 8 pin connectors and an adapter. Workloads with up to 600W consumption were used in the tests. The power supply easily delivered 600W, delivering slightly more than 300W per 8-pin even though they're only rated at 150W each.

If you are planning to buy a new generation performance graphics card, it is useful to be careful about the power supply and especially the adapter. For example, NVIDIA's new flagship RTX 4090 is listed with a TDP of 450W for reference, although it is said that specially cooled cards can consume over 600W. In fact, figures such as 800W were mentioned in some rumors. However, AMD's Radeon RX 7000 series graphics cards will also consume more power than the previous generation. In addition, when overclocking is involved, everything will take a different turn.

This was clarified by testing with dual 8-pin and three 8-pin power adapters for power consumption of 600W and 450W, respectively. A Gen 5 connector can handle up to 55 Amps, so 600 watts (50A) is within that limit.

12VHPWR connector to 2 x 8-pin adapter at 600W load:

• 1 x 8-Pin connector = 25.4A or 304.8W (2x increase over 150W)
• 1 x 8-Pin connector = 25.1A or 301.2W (2x increase over 150W)

12VHPWR connector to 3 x 8-pin adapter at 450W load:

• 1 x 8-pin connector = 25.34A or 282.4W (88% increase over 150W)
• 1 x 8-pin connector = 7.9A or 94.8W (within 150W power rating)
• 1 x 8-pin connector = 6.41 or 76.92W (within 150W power rating)

As a result, Gen 5 and ATX 3.0 compatible power supplies are recommended for those who are considering buying a new generation powerful graphics card. PCI-SIG is investigating adapter concerns and we will continue to share future developments with you.

Summary of the situation

• The 12VHPWR connector is designed for 600W.
• The single 8 pin connector is designed for 150W.
• Under 600W/450W load, more than 150W can be drawn through the 8-pin connector of the 16-pin to 2×8-pin splitter cable.
• The current is not well balanced on the 16pin to 3x8 pin splitter cable.
• The native 12VHPWR connector is recommended for high-power situations such as video cards.