With the next-gen launches just around the corner, one of the main components users want to update their PCs with is the PSU. This is due to new requirements and standards set to provide sustained, clean power, avoiding problems with transient spikes and power fluctuations. While there are many manufacturers bundling Gen 5 (12VHPWR) connectors into their existing PSUs, here’s why investing in a real ATX 3.0 compliant PSU of his is far better.
Here’s why you need to get an ATX 3.0 compliant PSU with a proper Gen 5 (12VHPWR) connector:
PSU manufacturers are gearing up for the grand launch of their products. New ATX 3.0 designHowever, there are also certain manufacturers who bundle their existing ATX 2.0 PSUs with Gen 5 connectors. As expected, future graphics cards are very power hungry, requiring up to 600 watts of power.
12What is the VHPWR connector?
The 12VHPWR auxiliary power connector is designed to deliver up to 600 Watts directly to PCIe* add-in cards. This power connector is not compatible with existing 2×3 or 2×4 auxiliary power connectors. The 12VHPWR connector has 3.0 mm spacing between power pins, while the 2×3 and 2×1 connector contacts have a 4.2 mm pitch. The 12VHPWR auxiliary power connector has 12 large contacts that carry power and 4 smaller contacts below that carry sideband signals.
ATX 3.0 12VHPWR Connector Specifications
Connector performance requirements are:
- Power pin current rating: 9.2 A per pin/position (excluding sideband contacts), all 12 contacts energized, limited temperature rise 30 °C above ambient temperature conditions at =12 VDC. The connector body must display a label or embossed H+ letter indicating support for 9.2 A/pin or greater. 12VHPWR Right Angle (R/A) See the approximate location of the marker on the PCB header.
What is the difference between ATX 3.0 Gen 5 and ATX 2.0 Gen 5?
To meet the 600W power requirement, the graphics card will be equipped with one PCIe Gen 5 (12VHPWR) connector or three 8-pin connectors. If you’re using an existing ATX 2.0 PSU, your only option is to boot the card with a Gen 5 adapter or three 8-pin connectors. For an ATX 3.0 PSU with a Gen 5 plug from the main unit, you don’t need to worry about adapters as the PSU connects directly to the graphics card.
Most manufacturers now say that using a standard 8-pin to 12VHPWR adapter should work fine, but according to PCI-SIG, it doesn’t. As you can see, the 12VHPWR Gen 5 connector is designed for a maximum load of 600W and the 8 pin connector is designed for a maximum load of 150W. And here comes the safety risk.
Below is an email forwarded by PCI-SIG regarding the safety risks associated with using Gen 5 PSUs that are not ATX 3.0 compliant.
Dear PCI-SIG Members,
Note that the PCI-SIG is aware that some implementations of 12VHPWR connectors and assemblies have demonstrated thermal variations that may cause safety issues under certain conditions. please give me. The PCI-SIG specification provides the information necessary for interoperability, but does not attempt to cover all aspects of good design. It relies on a number of industry best known methods and standard design practices. The PCI-SIG workgroup contains many knowledgeable experts in the fields of connectors and system design, so we examine the information available on this industry issue and help with solutions to the right extent. .
PCI-SIG may provide further updates as more details become available. In the meantime, members are encouraged to work closely with their connector vendors and exercise extreme caution when using high power connections, especially where there are safety concerns.
thank you very much,
The email clearly states that there are safety risks associated with PCIe Gen 5 connectors that have shown temperature differentials in PCI-SIG’s own tests. I wanted to find out the truth about this issue, so I figured out what caused it in the first place and what I did with the following test results.
Real-world testing with Gen 5 power adapters shows uneven load balance
So we used existing Gen 5 PSUs from major PSU manufacturers to see the thermal, and more importantly power, differences between a single Gen 5 connector and a 3x 8 pin to Gen 5 adapter. We set up a 600W load environment and used a Gen 5 adapter with a 12VHPWR connector on one end and two 8-pin connectors on the other. The 12VHPWR connector was plugged into the GPU and the two 8-pin connectors were plugged into the PSU.
Each of the two 8-pin connectors reaches a maximum power of 25A or about 300W. This is double the peak power rating of 150W. This is where the PCI-SIG reports the source of thermal fluctuations, but the problem is not only with the high power running through the 8-pin connector, but also with the way the load is distributed through the adapter .
For our second test, we set up a 450W test load using an NVIDIA GeForce RTX 3090 Ti graphics card. Here I used the reference adapter that came with the card, 12VHPWR to 3x 8 pin connectors. Here, instead of splitting the load evenly across all three connectors, one 8-pin connector will do 23.5A or 282W and the rest will draw 6-8A (80-100W). So even with three plugs, the single 8-pin connector is still a safety issue.
Some adapter cables with better materials such as alloy copper can tolerate more than 7A per pin, so 3 pins would be 21A, but still 3x power especially for long time use Stability and safety cannot be guaranteed under Excursion.
600 watts (50A) is well within that limit, as Gen 5 connectors can sustain up to 55 amps, and can sustain 3x transient spikes for the ATX 3.0 standard they are designed for. Here’s a breakdown of the two tests:
600W test load from 12VHPWR connector to 2 x 8 pin adapter:
- 1 x 8 pin connector = 25.4A or 304.8W (2x increase for 150W rating and above)
- 1 x 8 pin connector = 25.1A or 301.2W (2x increase for 150W rating and above)
450W test load from 12VHPWR connector to 3 x 8 pin adapter:
- 1 x 8 pin connector = 25.34A or 282.4W (88% more than 150W rating)
- 1 x 8 pin connector = 7.9A or 94.8W (within rated power 150W)
- 1 x 8 pin connector = 6.41 or 76.92W (within rated power 150W)
Using the Gen 5 connector directly from an ATX 3.0 PSU will not cause any heat or power fluctuations as the cable is rated to withstand heavy loads of up to 600W in a single cable. This may not be a big concern right now, but considering the expected 3x power spikes in next-gen graphics cards (1800W-600W x 3), this is a big concern for his PSU’s over-current and over-power May start functioning. As a result, when it hits the power wall, it loses power and shuts down the PC. So, to keep your PC running smoothly, we recommend investing in his PSU that is Gen 5 and ATX 3.0 compliant. As more information becomes available from the PSU manufacturing community and the PCI-SIG itself, we will provide updates on this issue.
- 12VHPWR connector is designed for 600W
- The 8-pin connector is designed for 150W.
- With a load of 600W/450W, more than 150W of power is delivered from pin 8.
16-pin to 2×8-pin splitter cable connector.
- A 16-pin to 3×8-pin splitter cable has unbalanced currents.
- Native 12VHPWR connector for high power demanding applications such as graphics
With that said, if you’re planning on building a new gaming PC with either the RTX 4090 or RX 7900 XT, it’s a good idea to get a PSU within the respective wattage range of the ATX 3.0 standard. Recommended. Currently, several PSU manufacturers such as MSI, ASUS, gigabyte, FSP group thermal take, seasonal, silverstone & cooler master announced PCIe Gen 5 & ATX 3.0 compliant designs.