PC doesn't boot with second PSU on. 6 GPUs (GTX 1070)

[wolverine31634]

Hello everyone,

This is my first mining rig for Ether. I finally managed to get my hands on on 6 1070 8 GB GPUs for Ether mining. Following are the Specs:

Motherboard - Asus Prime Z270-A
CPU - Intel Pentium G4400 @3.30 GHz
RAM - 4 GB Corsair
HDD- 120 GB Samsung EVO
GPUs- 5 Founder's Edition 1070 -8 GB and 1 PNY 1070 8 GB
PSU - 2x 750 Watt EVGA Supernova 750B, I am using one for mobo, CPU, HDD and 3 GPUs
Second for purely 3 GPUs (with that 24 piun connector shorted)
OS - Windows 10 pro

So my problem is if I turn both PSUs, PC doesn't boot. it gets stuck on a black screen with blinking white cursor (?) on top left corner. And if I turn the second PSU after system has booted it does not recognise those 3 GPUs powered by second PSU.    

I am not an expert PC builder so please let me know if I am making any stupid mistake. I am not even sure if I need 1500 Watt or I could do with just 750 watt. I did this way cuz it was cheaper this way and I figured I would get enough 6+2 pin connectors. I watched ANgry Chicken's, Guntis Vitolins', bits be trippin's videos on youtube, nobody seems to be facing such issue.

One weird thing i observed is, GPU fans turm on for all 6 GPUs even if only main PSU is on and second PSU is off. Only power it would get is from the risers which are powered by main supply, cuz I read anything on Mobo directly shoould be same PSU (?).

Thank you for your help. If anyone wants to know what price i got GPUs for or has rate, I wud be happy to share.

[1714979290]

1714979290

[philipma1957]

This belongs in alt coins.

I asked for it to be moved

Okay six risers correct?

Three cards on first psu.

Are wired to three risers correct?



The second psu is doing three cards

On three risers.  So it only has its wires attached to the risers and the 3 gpus correct?

Are the power risers correctly attached to mobo?

Try running three on the first psu.

And one on the second psu.

[wolverine31634]

Thank for the reply.

Yes six risers. All powered by by main PSU. Risers attached to motherboard thorough 1x PCIE which came along with the riser. its the blue USB cable connecting. Connections are okay because 3 are working and hashing.

[car1999]

you need an adapter to sync the the PSUs, like this one:
http://www.ebay.com/itm/18AWG-Dual-24-Pin-Female-to-24Pin-20-P-Male-Workstation-Server-PSU-Adapter-Cable-/322394161300?hash=item4b10308094:g:P8EAAOSwi8VZVLoC
good luck!

[Ahead]

Thank for the reply.

Yes six risers. All powered by by main PSU. Risers attached to motherboard thorough 1x PCIE which came along with the riser. its the blue USB cable connecting. Connections are okay because 3 are working and hashing.

Hi,

The riser of each card needs to be powered with the same PSU as the card.
example:

PSU1: motherboards, CPU, HDD, risers 1,2,3 and the GPUs 1,2,3 (sitting on risers 1,2,3)
PSU2: risers 4,5,6 and GPU's 4,5,6 (connected to risers 4,5,6)

DO NOT mix risers and GPU's on different PSUs!

Also if you are powering up the 2nd PSU manually, make sure it is powered up 1st! and then power the motherboard!