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Hey everyone,

I have 24 Gigabyte 1070ti cards (single 8pin power) inbound right now and would like some advice for powering 8 cards per mining machine.

I have 2x EVGA 750w G3 PSUs and I’m looking for advice on how to wire everything up. Currently I’m thinking of one PSU powering the motherboard, cpu, ram, SSD, and 3 GPU + 3 PCIe risers. The second would power 5 GPU + 5 risers. Might be a dumb question but can I use the CPU lead to power GPUs from the second PSU?

Right now my plan was to split the 8pin GPU and 6pin GPU leads, so one 8pin from the PSU powers the card and riser. Unless I’m able to use some molex/sata leads for powering risers (I’ve read that SATA is not a good choice though). The risers I have have three power options; 6pin, 4pin molex, or SATA.

Any advice would be greatly appreciated so that I can safely power everything. Worst case is I move to 6gpu per a machine or upgrade power supplies.

Thanks!

No the CPU plug is wired differently and you will make things go boom if you try and use it.

Well that’s good that I asked then. Thanks for letting me know about that. I’m just trying to find a good split to power all the GPUs (if it’s even possible). I’m 100% sure I can’t power GPUs with 4pin molex or SATA.

2x EVGA 750w G3 does not have enough VGA ports to power 8 GPUs and risers unless you split them. You could do this, but I don't use 2 PSUs when 1 will suffice.

I would just throw all 8 GPUs on one 1600w T2 or P2. Those have 9 VGA ports. You can also mix/match PERF cables into the SATA ports on the PSU so you can run all of your risers directly from PSU Molex cables and all of your GPUs on a single 8-pin cable. EVGA sells extra cables specifically for each of their PSUs so you can have exactly what you need.

I see, I’m trying to keep costs down and maximize ROI but if that’s the best route to take then I’ll definitely look into ordering a single large wattage PSU. Thanks for your advice!

A 1200W server PSU will provide enough power and have enough cables while being 1/3 the price of a 1600W ATX PSU.

What would you suggest? I have no experience with server power supplies. Is there a specific brand that you would recommend? It would be pretty awesome to have a single power supply that doesn’t cost over $350.

Check out https://www.parallelminer.com/. You can connect up to 16 PCI-E cables to a single breakout board and split each of them for 32 6+2 Pin connectors for GPU and risers.

If you are running the cards at efficient settings, run 4 card + risers from one PS, run MB/etc + 4 other cards from the other PS.

You have enough connections to do that easily - 5 cards per is problematical as there aren't enough ports on the PS to go around without doing SOME sort of splitter stuff.

Any other sources? I’ve looked at these power supplies before while researching and they are still out of stock.

The breakout boards themselves are still in stock on Parallelminer- you can opt to buy those and 6pin cables to attach onto the boards and buy the PSU separately, perhaps from eBay. It's only the complete kits OOS atm.

Alright yeah I see what you mean, so any server power supply should work with the breakout boards correct? Or is there a certain type of server PSU that is required for these breakout boards?

On 8 1070’s wouldn’t 2 750’s be right on the edge. I pull 1250 watts from 8 x 1070’s running at 65-75 percent power. I run 2 x 850’s in my 1070 rigs.

How are you powering the GPUs? What brand PSU are using? It would be nice to use off the shelf equipment, looking at these server power supplies I’m not seeing how I’ll be able to power the motherboard or other devices in the system.

Kill A Watt measures AC power at the wall while power supplies are rated by how much DC watts they are designed to deliver.

After reviewing the cables that are included with the power supply, I think it will be able to work. It includes 4 VGA power cables so I can power 4 GPUs from each power supply. Although I may move the SSD over to the second power supply to help with the first one having to deal with the motherboard. All fans will also be ran off the second power supply as well.

If I have stability issues or I'm pulling too much from one power supply. I'll upgrade to either the suggested server power supplies with break out boards, upgrade to a massive 1200+ watt regular power supply, or upgrade the EVGA 750w to EVGA 850w power supplies.

 The most efficient settings for the 1070 ti (NOT THE 1070) put the TDP at about 104 watts (slightly under 60%), which is only 416 watts.
 My 5-card "mix of 1070/1070ti/1080" rigs run all the cards in the 104-110 watt range and only pull 700 watts AT THE WALL despite using somewhat power hungry AMD 8320e CPUs for the most part - which is going to be more like 640 watts out of the PS itself (I do run them on Seasonic X-850 PS for the most part, one on a SS-860, as those have enough CONNECTIONS that I don't need to use splitters - but from a "handle the power" standpoint the EVGA G2/P2/T2 series would be fine).

 A 750 should easily handle an entire 4 card rig if running the cards at EFFICIENT settings, much less splitting an 8-card rig between 2 of the PS.

 Don't run the SSD on a power supply seperate from the MB - power draw is too low and too likely to do ground loops.
 Fans on the second PS make perfect sense.

My response is a bit late, but the breakout boards should specify which server PSUs work in either the title or in the description of the product. Not all server PSUs work with all breakout boards.

Yeah, as others have pointed out, that's not going to work.

1) 2x 750 PSU's are not enough for 8 1070 TI's.  You can manage with 2x 850's.
2) You will have to put 4-4 GPU's on each PSU because I believe the G3 850 only has 4 GPU slots (therefore the 750 G3 will not have 5+).

If you don't already know this, you will need a Daisy Chain to link the PSU's to your mobo.

 2 x 750 are PLENTY for 8 1070 ti cards running at EFFICIENT settings.
 An 850 is enough for *5* of them at efficient settings with a fair bit of headroom.

 The issue is a combination of 4 VGA + 4 SATA/Perph slots on the PS, NOT just the VGA slots (which have DUAL power cables avalable).

Yeah, you're right.  1x 1070 ti consumes 180 kw/h.  80% of 750 = 600 watts safe capacity.  You can have 4x 1070ti's running on 80% TDP and you will be fine.  My 1070 ti's run on 65% power and are very efficient.