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Topic: Connecting GPU's with and w/o Risers - page 2. (Read 278 times)

newbie
Activity: 25
Merit: 0
February 07, 2021, 07:38:21 PM
#6
This might be a dumb question but...any issues connecting some GPU's directly on the motherboard and some using risers?

Most mining rigs I see in the internet either have all their gpu's connected on the motherboard or all via risers.

I'm planning to use Asus Z370-E for my rig.

You have to understand how a GPU is powered.
Some power come from the PCI-E slot (75W max on PCI-E 16x slot) and some power come from the 6/8 pins PCI-E connector(s) of the GPU.

The motherboard is compatible with SLI/Crossfire, so at least using 2 PCI-E slots directly is totally fine. Because it's design to give power simulteously to 2 GPU from the PCI-E slots.
If you want to use more GPU, you have to use powered risers (like USB risers) so the power draw that the GPU expect from the slot will not come through the motherboard (and it's a good thing, because it will not be able to safely provide so much power to 4-6 GPU on the slots).
The power will come from the risers with the molex or sata power cable directly from the PSU.

Do not use to much risers on 1 PSU cable.
For exemple, if you have 1 SATA cable from the PSU with 5 SATA plugs ... do not plug 5 risers, be cause it could stress this cable.
I prefer to have max 2 risers per cable on the PSU

Okay I see. I will have two separate 850w PSU's to power eight 3070. I'll make sure to distribute powering the risers between the two psu's. Thanks!

hero member
Activity: 789
Merit: 501
February 07, 2021, 07:19:56 PM
#5
This might be a dumb question but...any issues connecting some GPU's directly on the motherboard and some using risers?

Most mining rigs I see in the internet either have all their gpu's connected on the motherboard or all via risers.

I'm planning to use Asus Z370-E for my rig.

You have to understand how a GPU is powered.
Some power come from the PCI-E slot (75W max on PCI-E 16x slot) and some power come from the 6/8 pins PCI-E connector(s) of the GPU.

The motherboard is compatible with SLI/Crossfire, so at least using 2 PCI-E slots directly is totally fine. Because it's design to give power simulteously to 2 GPU from the PCI-E slots.
If you want to use more GPU, you have to use powered risers (like USB risers) so the power draw that the GPU expect from the slot will not come through the motherboard (and it's a good thing, because it will not be able to safely provide so much power to 4-6 GPU on the slots).
The power will come from the risers with the molex or sata power cable directly from the PSU.

Do not use to much risers on 1 PSU cable.
For exemple, if you have 1 SATA cable from the PSU with 5 SATA plugs ... do not plug 5 risers, be cause it could stress this cable.
I prefer to have max 2 risers per cable on the PSU
full member
Activity: 600
Merit: 152
February 07, 2021, 06:45:09 PM
#4
try to keep those on the motherboard to a minimum.  1 or 2 shouldnt be a problem.  but air flow and power draw are concerns.  Be sure to plug in any supplimental power.  Some boards have an 8 pin cpu + another 4 or 8pin cpu or 4 pin molex at either or both ends of the slots.  Some even have 6pin pcie plugs like gpus and risers take. 


But whatever you plug directly in the motherboard will be pulling power through the traces of the board.  Its why most rigs are built with risers...that and airflow airlow airlow.


Got it thanks!

I was only planning to plug in one GPU. The rest will be on risers.

I'd put them all on risers to get more airflow. Heat is the enemy of any miner!
newbie
Activity: 25
Merit: 0
February 07, 2021, 05:51:02 PM
#3
try to keep those on the motherboard to a minimum.  1 or 2 shouldnt be a problem.  but air flow and power draw are concerns.  Be sure to plug in any supplimental power.  Some boards have an 8 pin cpu + another 4 or 8pin cpu or 4 pin molex at either or both ends of the slots.  Some even have 6pin pcie plugs like gpus and risers take. 


But whatever you plug directly in the motherboard will be pulling power through the traces of the board.  Its why most rigs are built with risers...that and airflow airlow airlow.


Got it thanks!

I was only planning to plug in one GPU. The rest will be on risers.
full member
Activity: 1275
Merit: 141
February 07, 2021, 05:16:37 PM
#2
try to keep those on the motherboard to a minimum.  1 or 2 shouldnt be a problem.  but air flow and power draw are concerns.  Be sure to plug in any supplimental power.  Some boards have an 8 pin cpu + another 4 or 8pin cpu or 4 pin molex at either or both ends of the slots.  Some even have 6pin pcie plugs like gpus and risers take. 


But whatever you plug directly in the motherboard will be pulling power through the traces of the board.  Its why most rigs are built with risers...that and airflow airlow airlow.
newbie
Activity: 25
Merit: 0
February 07, 2021, 05:05:48 PM
#1
This might be a dumb question but...any issues connecting some GPU's directly on the motherboard and some using risers?

Most mining rigs I see in the internet either have all their gpu's connected on the motherboard or all via risers.

I'm planning to use Asus Z370-E for my rig.
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