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Journeyman III

Help connecting Asrock Radeon RX VEGA 56 8GB HBM2 Phantom Gaming

Hello forum and helps in advance for trying to help me.

I just bought an Asrock Radeon RX VEGA 56 8GB HBM2 Phantom Gaming video card, but my power supply is a Cooler Master Silent Pro M700.

It is a modular power supply that has two Pci express 6 pin slots outgoing, and the video card needs an input of two 8 pin cables.

I've been going mad reading stuff in both manuals, but can't piece it together.

This is what the power supply user manual shows:

And all I could find in the Asrock web pages was that the card has 2 x 8-pin connectors (which I alredy know) and that the recommended PSU is 650W.

But I don't understand a lot about voltages and pc wiring, can someone please tell me how to connect it? My gut tells me to buy 2 cables with a 6 pin to 8 pin conversion, and plug both 6 pin ends into both my PSU outgoing slots and the other two 8 pin ends to the video card, but I don't know if this will overpower the card and might fry it, or perhaps that's exactly what must be done.

Can someone please help me? I'm sort of desperate.

4 Replies

If your PSU does not have PCIe 8 pin connectors, then you should NOT attempt to use Molex-PCIe8 adapters to power the card. You should replace the PSU with a modern model capable of at least 55A at +12v, and featuring 2 or more PCIe 8 pin connectors.


Hey black_zion and thank you for your reply.

I was not going to use molex adapters. The PSU has 2 6 pin outputs, I was thinking of connecting a 6 pin cable to the PSU and another 8 pin end to the GPU, and do this for both slots.


Don't run that card with that power supply, full stop.


Thank you for your feedback black_zion. I just placed an order for a Thermaltake Smart Pro 750W Bronze which has 62.5A at +12V and I guess will exceed the requirements for this GPU. I wouldn't have done it without your advise and could've made a huge mistake.