Bitcoin Forum

Hey guys, I recently purchased a used s7 off ebay and it came with 2 power supplies. The issue i am having is that each power supply only has 8 pci connectors.

Is it a bad idea to only attach 2 connectors to each hash board? It seemes to boot up but I'm hesitant to run it like rhis..

What id like to know is 1. Is this at all risky? 2. Does this reduce the efficiency of my miner? If any of these are yes, what do you guys suggest as a power supply? The official bitmain one, or something else?

And what size are the 2 PSU's it came with? Around 750W each? The s7 unless modified for under-voltage/under-clock pulls about 1,200-1,400w fro the wall depending on the model. Yes all the PCIe sockets need to be used.

If feeding a miner from 2 supplies DO NOT connect 2 supplies to 1 board because the 2 supplies will fight and damage each other as well as possibly the hash board.

okay  you  don't want 2 psu's  soooo easy to short the gear.




you can take 1 psu and run  with 2 cable per board  and one cable for the controller.

if the psu is rated for 1200 watts  and you adjust the frequency down just  a bit

if you lower the hash rate to about 4200  it would take about  1100 watts  and would work.

the exact name and model of the psu's please

Being conservative I would say a full speed s7 pulls about 450w per board + 50w for the controller which powers the beagle and the fan.


If you are running 2 PSUs I would run them like this


PSU 1 = Hash board 1 + hash board 2 = 6 PCIe plugs required

PSU 1 = Hashboard 3 + Controller = 4 PCIe plugs required.

Make sure you turn on PSU 1 first so that when PSU 2 boots the controller, it sees all of the hashing boards.


NEVER connect more than one PSU to a single board. This will fry your hardware.


As long as PSU 1 is rated for 1100 watts or more you should be fine.

As long as PSU 2 is rated for 600 watts or more you should be fine.