PSU Recommendations For 8x 5700XT Rig

I am fairly new to all of this. I currently have a 6X 1660S rig that is in an enclosed case. And now I am planning towards building my next mining rig with 8 5700XTs. But where I am stuck is the PSU. For the 1660S rig, I got a killer deal on a used EVGA 1200 P2 which easily powered the whole rig and since the cards don’t draw that much, I felt comfortable using splitters to use one power cable to power the riser and the card.

But for the 5700 XT rig, each card uses a 8+6 pin and of course, there is still the riser. So I have pretty much decided to bring in a server PSU since ATX power supplies are fairly expensive right now. But this is where I am lost.

Do you have a favorite place to order a server PSU and cables from? Nerdgearz seems to be perpetually sold out.

In a rig like this would you run a separate cable for each 8pin and 6 pin for the cards separately (meaning 16 cables just to the GPUs) or would you feel comfortable using cables that are 6pin to dual 6+2 pin to power each GPU?

Or maybe I am overthinking this and I and I should just go with 2 ATX PSUs. I don’t know.

Thanks for any input.

To be honest, i have not had much luck in powering my AMD newer cards with a server PSU. I wound up going with a 1200w ATX and a server PSU. The thing about the server PSUs is they run freaking hot.

You only need 1 ATX PSU. Buy the risers that have SATA connectors. most better PSU have at least 4 SATA. Run 3 risers with 1, 3 with another, and 2 off a 3rd. Then use 4th for HDD. I got my 1600w PSU for about $200 and it runs cool and sweet.

BTW, I’m running 3 Radeon VII and 2 580s with that 1600w alone. That’s 8 gpu and 5 riser cables.

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The larger power supplies have more pcie ports, more sata ports and more peripheral ports than the smaller supplies.

Many Risers can be powered either by 4 Pin Molex, SATA, and 6 pin Pcie. Risers also consume the least power so can be adapted with splitters if necessary.

A 1300 Watt power supply may look like this:

Which would work fine with GPU’s having one 8 pin power connector. However, to power 8 GPU’s with Dual 8 pin power connectors you’ll need a 1600 Watt power supply like this in Gold or Titanium.

GPU’s with 2 eight pin power connectors can be fed from one 8 pin cable attached at the power supply Pcie port with either the cable has 2 eight pin plugs on the GPU end, or use a bumble bee colored 8 pin to 2 6+2 pin splitter. That takes care of only one card so unless you have the 1600 Watt power supply, you will run out of Pcie ports after 4 or 6 cards depending on the power supply.

To add additional 6 pin pcie power for risers you can use one CPU power 8 pin to a 4+4 pin cable with an adaptor sold at Amazon that rewires it to be another Pcie cable. Use this with the 8 pin to two 6+2 pin splitters splitter to power two more risers or another GPU. You’ll need the other CPU port for your motherboard.
Here is the adapter:


and the splitter:

https://www.amazon.com/JacobsParts-Express-Power-Splitter-Cable/dp/B07611QXG4/ref=sr_1_16?dchild=1&keywords=pcie+8+pin+splitter+adapter&qid=1599028656&sr=8-16

Can’t guarantee the power connection is correct for the risers, but I’m pretty sure it will work for two riser cards using the splitter below with the extension cable further down. SATA or Molex direct from the power supply would also work for risers but 6 pin pcie has the best current handling capability.

https://www.amazon.com/Tan-QY-Graphics-Y-Splitter-Extension/dp/B07HKTFVXG/ref=sr_1_12_sspa?dchild=1&keywords="6+pin"+pcie+splitter&qid=1599032558&sr=8-12-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzOENGUUlNN0o4SldLJmVuY3J5cHRlZElkPUEwMzIwNjczMUhOVVFFUklMRE5CMyZlbmNyeXB0ZWRBZElkPUEwODI0Nzc1Mjk3NTlVWTlDSk5GNSZ3aWRnZXROYW1lPXNwX210ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

https://www.amazon.com/Express-Adapter-Graphics-20-inches-TeamProfitcom/dp/B07D8QBN79/ref=sr_1_5?dchild=1&keywords="6+pin"+pcie+cable+male+male&qid=1599032796&sr=8-5

I would test it first as the positive all on one side and negative all on the other side should work for the Riser cards fed from the peripheral and sata ports on the power supply.

You could also use two smaller power supplies and the relay or 24 pin adapter to start both power supplies at the same time.

Never plug more than a 1600 watt power supply into any circuits fed from one circuit breaker.

I am leaning more towards the 2 smaller ATX PSU route I think. I might be able to get 2 EVGA 1000 G2s cheap on the used market close by, but they didn’t come with any cables. I am planning on using B250 mining expert since that is what I have on hand so I don’t need the adapter to use the two PSUs.

Thank you for both for the great information.

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Well I grabbed a EVGA 1300 G2 used today so I can start assembling things as I watch the power at the wall. Then I will know if I need to add a second PSU for this build as I get more cards.

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For mining, I use the EVGA 1300 G2 also. Since power supply prices have risen so much lately even on the used market, I often look at the prices to compare. I bought mine with shipping for $70-$75 and I bought like 4 for them. I use the 1200 Platinum in my personal PC. Still can’t afford Titanium.

Todays best value is in the 850 Watt range, used. Once you get to 1000 watts the prices and shipping get well over $100. The bigger ones $200, $300 on up. Used!

Once again, be careful loading two of these 1300 watt power supplies up as you may burn a receptacle before tripping a breaker. I Strive for the most hashpower per Watt as power goes up faster than the hashrate as you increase your power level and clocks.

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