Connecting GPU's with and w/o Risers

[mantonio333]

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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[miner29]

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.

[mantonio333]

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.

[Sledge0001]

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!

[th00ber]

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

[mantonio333]

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!

[Sledge0001]

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!

If you choose to use 2 PSU's then you need to make damn good and sure that you select a single PSU to power up both the riser and GPU. DO NOT mix the power sources on risers and GPU's or you can cause damage to your equipment and possibly start a fire!

[JayDDee]

Newbie should avoid multi-PSU, keep it simple to start.
Regarding the initial question, connecting 2 GPUs directly to the motherboard is
fine if the x16 slots are properly spaced. It will run a little hotter but saves one
extra power connection. There is some good discussion in recent threads about how
to power risers. TLDR: SATA is bad.

[KuromaYoichi]

Are you going to mine inside a case? because usually the one that want to connect 2 GPU directly to the motherboard doen't use open case. It's okay but the temperature will be higher than using riser because you will space them properly. You'll probably run into thermal throttle if you are planning to use 3080 / 3090 but other than that i think it will be okay. I've seen someone open the side panel and using 1 riser for the 2nd gpu.

[Stanlo]

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!

If you are planning to power 8x RTX3070 it will be wiser to buy power supplies with 1200watt capability because a single RTX3070 draws up to 117-120watts per gpu now do the math, that's 960 watts and motherboard and CPU will need some power too

[TanakabZX]

It makes more sense to use risers for all the graphic cards to get better cooling, if you insert a card into the 1st pcie slot and use riser on others there will be heat because a card is underneath doing a hardwork too, user risers and create space between the gpus

[mak013]

I used motherboard PCI-e without risers only in 2 choices: it was test rig for 1-2 GPUs and I mistaked and had not enough risers but had reserve PSUs and motherboards.
It will work fine but it will not be easy to construct normal rig with different GPU connection.

[fmz89]

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.

only heat the issue but if youre running on water cooled grapics it will be more stable gpu direct on pcie mobo, there is 7 / 8 full pcie mobo and put all together with small  case and only gpu blower fan will do the trick, or all liquid cooler will be nice for looking and silent with lower gpu consumption just for hobbies

[th00ber]

If you choose to use 2 PSU's then you need to make damn good and sure that you select a single PSU to power up both the riser and GPU. DO NOT mix the power sources on risers and GPU's or you can cause damage to your equipment and possibly start a fire!

So true !
https://www.thegeekpub.com/11955/using-dual-power-supplies-mining/

The key is :
Everything you plug on the MB comes from one PSU (24 pin, CPU pin, molex etc ...)
Everything you plug for a GPU comes from one PSU (Riser power + 6/8 pins PCI-E connector to GPU)

So you will not mix the ground of the 2 PSU and everything will be fine  

[batsonxl]

im not sure how many pci lanes that mobo will support, you can try and see. if after some gpus you will not see in device manager then you are run out pci lanes because when you plug directly to 16x you will loose lanes. my msi x79 no problem 1 gpu plugged to 16x rest 3 out with risers.

[mantonio333]

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!

If you choose to use 2 PSU's then you need to make damn good and sure that you select a single PSU to power up both the riser and GPU. DO NOT mix the power sources on risers and GPU's or you can cause damage to your equipment and possibly start a fire!

Do you mean I need to make sure to connect each GPU/Riser pair on the same PSU each? For example, connect GPU/Riser 1-4 pairs on first PSU and connect GPU/Riser 5-8 pairs on second PSU?

[murgorx]

Hey,

if you are using dual power supplies do the following :
connect one GPU and its riser to power supply A until you have no more free slots.

Then go to power supply B , and connect each GPU and IT'S Riser to the same PSU!

Do not connect GPU_1 to PSU A and the riser of GPU_1 to PSU 2. Hope it's clear

[murgorx]

Also, check this diagram here :
https://3.bp.blogspot.com/-Yc7foXYMC58/WmUmqYWR_MI/AAAAAAAAAUk/dl5jRq-YLBUnmQj3JFCuxh5EFjRIj-r6gCLcBGAs/s1600/powerrig.png

A more clear representation of what I wanted to say with my post above.

[mantonio333]

If you choose to use 2 PSU's then you need to make damn good and sure that you select a single PSU to power up both the riser and GPU. DO NOT mix the power sources on risers and GPU's or you can cause damage to your equipment and possibly start a fire!

So true !
https://www.thegeekpub.com/11955/using-dual-power-supplies-mining/

The key is :
Everything you plug on the MB comes from one PSU (24 pin, CPU pin, molex etc ...)
Everything you plug for a GPU comes from one PSU (Riser power + 6/8 pins PCI-E connector to GPU)

So you will not mix the ground of the 2 PSU and everything will be fine  

Very useful article thank you! I was not aware that you couldn't mix and match psu connection with the GPU and mobo.

So basically I'll use the first psu for the mobo and 4 GPU/Risers. Then use the second psu isolated on the other 4 GPU/Riser pairs. This should be ok?

[mantonio333]

Hey,

if you are using dual power supplies do the following :
connect one GPU and its riser to power supply A until you have no more free slots.

Then go to power supply B , and connect each GPU and IT'S Riser to the same PSU!

Do not connect GPU_1 to PSU A and the riser of GPU_1 to PSU 2. Hope it's clear

Got it thanks!