Usage of 8-pin connectors and 12VHPWR connector between PSU and RTX 3090 [pictures]

Question

My PSU is 1000W Asus TUF Gaming Gold https://www.verkkokauppa.com/fi/product/867676/Asus-TUF-Gaming-1000W-ATX-virtalahde-1000-W

My GPU is MSI Suprim X RTX 3090 which needs three (6+2pin PCI-E) connectors.

I'm using only the power cables that came with the PSU and they have clear texts in each cable end such as "PCI-E", "CPU", "PSU" (to indicate the end that goes to the PSU)

My PSU has four 8-pin outputs except one has a bit different look on the square atop of the 8 holes. Can I use any of these PSU's 8-pin outputs to either the 8-pin CPU cable or the 8-pin PCI-E cables provided with the PSU? They all fit to all of them physically but of course the CPU end of the CPU cable doesn't fit the GPU's 8-pin connectors. Just the PSU side of each cable is identical.

Here's a pic of the PSU outputs. I've highlighted all the 8-pin outputs:

Question: Can I attach a 8-pin GPU and CPU connectors to any of the 8-pin outputs in the PSU?

Related question: If not, can I attach the following cable to the PSU's 12VHPWR output: 12VHPWR connector to the PSU and 2x 2+6pin PCI-E connectors to the GPU? And if I can, should I just connect one of the 2+6pin PCI-E ends of this 3-way cable to the GPU along with 2 separate 2+6 PCI-E cables from the PSU, OR one separate 2+6 pin PCI-E cable from PSU to GPU and both of the 2+6 PCI-E connectors from the 12VHPWR cable.

Here's a pic of the 12VHPWR -> 2x 6+2pin PCI-E cable:

Somehow it's nearly impossible to find an answer to this. Manuals are useless so I'll ask you gurus here. Thank you.

Answer 1

You can probably connect both CPU and PCIe cables to your PSU, but you need to make absolutely certain that the cable that goes to the CPU explicitly states that it is for the CPU/EPS_12V connector.

The outputs on the PSU are likely identical, the difference will be in how the end connector is wired up.

The extra 4 pin under one of those connectors is for current sensing on the 8 pin connector. Under incredibly heavy load, such as with a 4090 power supply votages can sag due to cable resistance and load and that sense is giving some feedback to the power supply so it can detect what is going on. Some more information is at This is how NVIDIA’s 4-way adapter for the 12VHPWR port of the GeForce RTX 4090 really works!

For the CPU EPS_12V and PCIe, the connectors look similar, are keyed in such a way that you could potentially plug one into the wrong socket with enough force, and have power on opposite pins.

I've written about the pinouts of those connectors here: I've pluged e-pci power cable(6+2pin) to eps 8 pin on motherboard