6x GPU 1080ti mining rig - Powering risers and GPU problems

I'm having problems with a 6x GPU mining rig (6xZotac 1080 ti extreme & 2x PSU Corsair HX1000i)

GPU powered like this:
GPU --> Dual 8 pin --> VGA (8PIN) in PSU (1 cable pr PSU). -
Hence; 1x8pin in PSU, and 2x 8pins in GPU. (8 pin to dual 8 pin)

Riser powered:
Riser --> 6 pin --> SATA-6PIN cable-chain (from Corsair) --> 6 pin from chain into PSU. (1 riser pr. sata-chain)

First question:
Will 1 pcs 8pin to dual 8pin to GPU be enough if you want to OC it?
(1x 8pin cable only provides 150W right, or it provides more when its dual 8pin?)
Or should I use 2 separate 8 pins to power 1 GPU.

Or can I power like this?

2 pcs 8pin to dual 8pin pr GPU.
1x 8 pin in PSU, and 1x 8pin in GPU (leaving 1 (6+2)pin un-used)
1x 8 pin in PSU, and 1x 8pin in GPU + the other 6 pin in riser).

This would make me possible to power 3x risers, and 3 1080ti from 6 outlets in PSU. (2 outlets pr. GPU)
(And no SATA or MOLEX problems powering the risers)

https://imgur.com/o0XIRDf

Topic: 6x GPU 1080ti mining rig - Powering risers and GPU problems (Read 110 times)