Dual PSU Advice

Hi, I’m about to setup dual PSU’s on my rig and have an add2psu adapter to connect them.

I’ve read that having dual PSU’s can cause a problem if they power components that draw power from both.

Is the best setup to connect 5 gpu’s to 1 psu, and 3 gpu’s and the risers and rest of the components to the other?

Or could could I power 4 gpu’s from each PSU and power the other components from both also?

Asus prime-A
8 x 1080ti
2 x EVGA 1200w PSU
1 x add2psu

Thanks for the advice!

As far as I know you should connect the riser and the card to one PSU(not separate), don’t “mix” the electricity. I’ve been using dual psu’s for a while now like that and I didn’t have any problems.

Please someone correct me if I’m wrong.

Oh, and use risers with molex not sata if you are using 1080ti’s.

Because I had exactly the same problem a few days ago but with 6 1080 Ti, if you overclock 8 x 1080 Ti, your system is going to be really “tight” with 2x1200 Watts.

Every card uses 250 watts, also u need watts for risers and motherboard etc.

For my case (6x1080 Ti), 3 PSUs x1000 watt. 2 GPUs + 2 Risers / PSU. Lastly, one PSU except from GPUs and risers has motherboard connected too.

You can do something like that for 8 GPUS.

Hey. Each GPU and riser pair should be plugged into the same PSU. I was told that powering a connected pair will cause a voltage feedback loop.

as long as your using usb powered risers you can set it up however you want
i personally pair risers and gpu’s to the same psu, but it actaully doesnt matter as the power from each are not connected

the nice thing about pairing, is its easy to figure out how much power your going to need per psu… it makes watt calculations easier

thanks for the advice my minds slightly more at ease that I’m not going to make my rig explode

do the usb risers draw 60w? I’m running my GPU’s at 225w so 225+60 = 285w x 4 = 1140w would not be leaving much room for the motherboard

I think, first 3 GPU + mobo use one PSU, the left 5 GPU go to second PSU.
Risers and modulars should go with the PSU and GPU together. For example, PSU1 goes with GPU0/GPU1/GPU3 then riser and its PCIE will connect with PSU1.
In Vietnam, we often use this one for dual PSU, only $4.

Just make sure that only one of your PSU’s powers the motherboard – meaning that the same PSU connects to the 24 pin power connector and the 8 pin CPU power connector (and if there are any molex power connectors on the motherboard) all should feed back to the same power supply.

If you split your power supplies like so: (1) EVGA, (1) server PSU with an X-adapter board, you can use Molex cables from the EVGA to power a couple of the risers, and then you can use 6-Pin power cables from the X-adapter to directly plug into the risers that have a 6-pin connector (not the molex connector) on the back. Parallelminer.com sells this type of setup and has lots of pictures if you want to check it out.

what i do, to simplify things, is take the tdp for each card and add a bit, and stick those cards and risers on one psu, add in 150 for mobo, cpu, ssd, etc.

then stick the other cards and their risers on a secondary or third psu

sites like pcpartpicker are good for figuring out watts each card needs, as a rough estimate… thats what i use to figure things out. simple, and has worked out perfectly for me so far

I now have the Dual PSU’s up and running and 4 GPU’s connected whilst I wait for the other 4 to arrive, however it looks like each EVGA 1200w P2 only has 6 VGA slots and as the 1080ti’s need 2 cables per card I can only run 3 per PSU.

Two of the VGA cables have a 4 pin connector and another 3 pin connector coming off it, pushing my luck I imagine but would this power another card or am I going to have to resort to a 3rd PSU?

I have a problem with Dual PSU, i already search deep in the web and i didnt find the answer, When i solo mining ETH everything is fine, but when i try dual mining or mining Zcash the second PSU just goes off after beginning and the claymore stops working… anyone knows why ? Everything is well conected, i dont understand why it stops… If anybody could help me i’d appreciate thankss …

You need to give A LOT more information that this. Spec of psu, # of GPU’s, software you are using, ETC

Are you dual mining with Zcash or dual mining eth and ?

Ok you’re right! I’ve got 6 x rx480 nitro+ 8gb, 2 PSU, the first 850 EVGA and the second EVGA 750 GQ. The second is connected by add2psu adapter. Im using claymore 9.8 and 12.6 for zcash. That occours when I try to mine Zcash SOLO and ETH + Decred / SC… When i solo mining ETH/ETC/Musicoin everything works fine…

Am I reading correctly?
When you are trying to mine Zcash AND ETH with Decred/SC at the same time and this is when you have your problem?

Or when you try to solo mine Zcash OR dual mine ETH and Decred/ SC you have the issue?

When you JUST mine ETH or ETC or Musicoin everything is fine?