Hi guys,
I’m trying to build a rig and I’m on a point where i am very confused.
This is the setup for my rig:
https://imgur.com/a/i8cwAThe PSU´s on the pic from left to right: 1-3
My setup:
3x 750w PSU
6x AMD R9 290
1x Mainboard: HM 76-65 BTCcombo
6x Riser (6 Pin to SATA)
CASE 1: CHECK
When i start my rig with only 1 psu (psu 1) everything works fine.
The psu consumes 600 W and powers the mobo + 2 cards + and 2 riser.
I can mine with this setup so everything so good so far.
CASE 2: CHECK
Now if i connect the other two PSU`S (psu 2 and psu 3) with ONLY ONE CARD,
So that totally 4 cards are connected and running:
PSU 1: 2 cards + mobo + 2 risers
PSU 2: 1 card + 1 riser
PSU 3: 1 card + 1 riser
This Setup although works fine and i have no problem with the rig.
The troubles come up with card no. 5 and 6.
CASE 3: Problematically
PSU 1: 2 cards + mobo + 2 risers
PSU 2: 2 cards + 2 risers
PSU 3: 1 card + 1 riser
If i connect now another card to psu 2 or 3 and start mining, psu (2 or 3) gets under load
and i can see how a random gpu fan stopps working, a few secons after that the PSU shut completly down.
Sometime before i started testing it again i saw the GPU Fans of one of them was still spinning even when the PSU was
already power off.
I thought the issue would be of some power consumption. So i started testing it with a power consumption meter:
GPU: 250w
Riser: 50w
Combined: stable 300w
Combined: 2 GPU 2 Riser = 600w
Realy strange is when i put the mobo on this psu the power consumption is still 600w .
So i start testing the PSU who is running without the mainboard and shut downs on mining.
The PSU reaching exact 600w before they shut down.
CASE 4: Same as 3
PSU 1: 2 cards + mobo + 4 risers
PSU 2: 2 cards
Nothing changed same result like case 3.
To combine all 3 PSUs iam using:
https://i.ebayimg.com/images/g/0X0AAOSwQwZags8j/s-l300.jpgHas anyone an idea what i am doing wrong?
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UPDATE: I started a view new tests.
Pluging all psus on wall outlet = nothing changed
Tryed some bios changes especially (gain1,gain2) = nothing changed
Connecting 1 psu with 2 gpus + 2 risers and started setting power limit on -10 -20 and so on
I`ve got power consumption: 500w it shuts down after view minutes of mining , then
440w it shuts down again!
The only conclusion that i can draw from the result is that: my 750w power supply is not able to run more than one graphics card at the same time if it is not connected to the mainboard, everything else is going well
And yes i am using extra splitter.