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EPYC 7551P 8-GPU Setup

Posted: Sat Mar 19, 2022 9:59 pm
by Skillz
Waiting on the PCI-e riser/extension cables to be delivered. I ordered some with power built into them so they can have their own power source instead of trying to pull it through the motherboard.

The breakout board is this: https://www.parallelminer.com/product/x ... -supplies/

Its got an ATX port, but it claims it can only sustain 180W through it.

I got a nice new power meter and have a full load on the CPU right now. It's reading 180W - 182W at the wall which means it should be ~10% less on the DC side. Correct? So I should be okay to run the motherboard through the ATX connector on the breakout board or should I use a standalone PSU to power it? Currently I am using a 500W EVGA PSU since I don't have any GPUs loaded on it yet.

Re: EPYC 7551P 8-GPU Setup

Posted: Sun Mar 20, 2022 7:49 am
by StefanR5R
Skillz wrote:
Sat Mar 19, 2022 9:59 pm
Its got an ATX port, but it claims it can only sustain 180W through it.
The 24-pin ATX connector has got two +12 V pins, each rated for 8 A max AFAIU. That is, this 180 W specification of the ATX port of your breakout board looks to be simply about the same limit as per the standard.

Any additional +12 V power to a mainboard needs to be implemented with extra connectors. E.g. the 8-pin EPS12V connector has got four +12 V pins and is rated for 288 W total.

Re: EPYC 7551P 8-GPU Setup

Posted: Sun Mar 20, 2022 11:22 am
by Icecold
The problem with that breakout board is that the 8 pin EPS connector is just jumpered off the main ATX connector. I wouldn't risk it on anything other than a super low power usage CPU like a Pentium dual core or something.

This image shows it clearly-

Image

If you were going to attempt it maybe use a 6 pin PCIe cable with an adapter to 8 pin CPU instead of the one jumpered off the ATX like this - https://www.amazon.com/inch-6PIN-PCIE-P ... B01EEOW3CA

Re: EPYC 7551P 8-GPU Setup

Posted: Sun Mar 20, 2022 11:58 am
by Skillz
Yes, that's correct. The 8 pin is attached to the 24 pin and the EPYC board needs a 8 and 4 pin CPU (EPS) connection.

Added in 38 seconds:
That adapter should solve the issue. I'll just get two of them.