PCI-SIG worried: possible thermal variance with PCIe 5.0 power cables

If you don't know already: next-gen power supplies are coming thanks to next-gen PCIe 5.0 graphics cards that will need to chew down more power, much more power.

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The new 12VHPWR cable plug connector

The new ATX 3.0 power supplies will include new PCIe Gen5 connector -- the new 12VHPWR power connectors -- and now the PCI-SIG organization is sending out emails to PCI-SIG members that it's concerned over "thermal variance" of using regular 8-pin PCIe power cables into 12VHPWR power adapters.

Why is this an issue? Well, until the last generation we were hitting around 300W maximum power consumption for most mainstream GPUs, while some cards were made to hit 450W like NVIDIA's last flagship GeForce RTX 3090 Ti graphics card. Even then, NVIDIA was using a new PCIe power connector that split from the 12-pin PCIe cable to 3 x 8-pin PCIe power connectors (150W per 8-pin PCIe power connector = 450W total) for its GeForce RTX 3090 Ti.

The PCB and cooling systems were tested by AIB partners, including the MSI GeForce RTX 3090 Ti SUPRIM X and ASUS ROG Strix LC GeForce RTX 3090 Ti OC Edition graphics cards that we reviewed when they were released earlier this year, as NVIDIA was preparing AIB partners for 450W+ designs.

• Read more: MSI MEG Ai1300P: world's first ATX 3.0 PSU + 600W PCIe 5.0 connector
• Read more: MSI MEG PCIe 5.0 + ATX 3.0 PSUs: ready for 3 x GPU power excursion
• Read more: Intel intros ATX 3.0, ATX12VO 2.0 standards, for next-gen 600W GPUs

16-pin power connector to 3 x 8-pin PCIe power connectors (source: TweakTown)

• Read more: PCIe 5.0 '12VHPWR' power connector: 150W, 300W, 450W, 600W settings
• Read more: PCIe 5.0 power connector allows up to 600W of power, for next-gen GPUs
• Read more: PCIe 5.0 GPUs can have 'power excursions', use up to 1800W of power

Do you have to worry about it? Not if you buy yourself a new ATX 3.0-compatible power supply when you purchase your new graphics card if it has the 16-pin Gen5 power connector. If the GPU genuinely requires up to 600W of power, then you're going to want to buy a new high-quality ATX 3.0-based PSU.

PCI-SIG is concerned about users that might buy a new GPU that uses the new 12VHPWR power connector, with power adapters from the new power connectors plugged into your old PSU. If the GPU starts having these "power excursions" and driving 600W+ and some... then those adapters might (probably) will run into issues.

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ATX 3.0 "12VHPWR" connector specs (source: Wccftech)

How? Well, the power cable adapters you'd need would need to go from the new 12VHPWR and into 3 x 8-pin or 4 x 8-pin PCIe power connectors... the triple 8-pin for 450W graphics cards, and quad 8-pin for 600W graphics cards of the future. There are safety risks with that obviously, but not if you buy an ATX 3.0-compliant PSU which has 600W-ready 12VHPWR power connectors.

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The new 12VHPWR cable plug connector

The email that Wccftech saw, explained:

Dear PCI-SIG Member,

Please be advised that PCI-SIG has become aware that some implementations of the 12VHPWR connectors and assemblies have demonstrated thermal variance, which could result in safety issues under certain conditions. Although PCI-SIG specifications provide necessary information for interoperability, they do not attempt to encompass all aspects of proper design, relying on numerous industry best-known methods and standard design practices. As the PCI-SIG workgroups include many knowledgeable experts in the field of connector and system design, they will be looking at the information available about this industry issue and assisting in any resolution to whatever extent is appropriate.

As more details emerge, PCI-SIG may provide further updates. In the meantime, we recommend members work closely with their connector vendors and exercise due diligence in using high-power connections, particularly where safety concerns may exist

Thank You.