Troubleshooting Multiple gpu setups that use Riser cards

San-Fernando-Valley
San-Fernando-Valley
Joined: 16 Mar 16
Posts: 206
Credit: 4,403,922,282
RAC: 730,268

+1    perfect again !

+1    perfect again !

Keith Myers
Keith Myers
Joined: 11 Feb 11
Posts: 1,319
Credit: 2,393,627,540
RAC: 7,780,626

San-Fernando-Valley

San-Fernando-Valley wrote:

... great answer!!

Many thanks for such an elaborate post.

 

But, the power reliance from the board is only needed with GPUs that don't have a discret/own power connector.  Or am I wrong with this assumption?

 

Again thanks:   Ian&Steve C.

Not accurate statement.  Many cards supplement their auxiliary power connectors by still drawing up to 75W from the PCIE slot.

 

Ian&Steve C.
Ian&Steve C.
Joined: 19 Jan 20
Posts: 884
Credit: 5,553,474,371
RAC: 32,065,358

San-Fernando-Valley

San-Fernando-Valley wrote:

But, the power reliance from the board is only needed with GPUs that don't have a discret/own power connector.  Or am I wrong with this assumption?

All GPUs require some level of power input from the PCIe slot, even if it has external power input. how much power is totally gpu model dependent. Some GPUs will pull the full 75W power spec from the slot, with extra coming from the external inputs, and some GPUs might pull nearly everything from the external power inputs with almost nothing from the slot. or somewhere in the middle. sometimes they might segregate power input for different components on the board like having VRAM/Fans/LEDs pulling power from the slot and GPU core pulling external power, or having some kind of power balancing circuit to power everything from both while not allowing more than 75W through the slot. there's no way to tell unless you test for yourself, as this will not be something specifically disclosed by the manufacturer.

of course a low power GPU that does not have external power input will need to pull everything from the slot. these will not exceed 75W for the whole GPU since that's the spec of the PCIe slot.

_____________________________________________

San-Fernando-Valley
San-Fernando-Valley
Joined: 16 Mar 16
Posts: 206
Credit: 4,403,922,282
RAC: 730,268

Ian&Steve C.

Ian&Steve C. wrote:

San-Fernando-Valley wrote:

But, the power reliance from the board is only needed with GPUs that don't have a discret/own power connector.  Or am I wrong with this assumption?

All GPUs require some level of power input from the PCIe slot, even if it has external power input. how much power is totally gpu model dependent. ...

Very interesting informations.

Now this is another top-notch answer.

I really appreciate your successfull efforts to get rid of my "brain fog"!

Have a nice day ...

Tom M
Tom M
Joined: 2 Feb 06
Posts: 1,119
Credit: 1,943,979,788
RAC: 4,911,374

Ian&Steve C. wrote: i think

Ian&Steve C. wrote:

i think we have the same size rack.

Nope.  While I still own  that rack the one I am using is significantly shorter and taller.  I now strongly suspect I will be migrating back to the "original" rack that AFAIK was the very first mining rack I ever bought.

I probably am going to buy 2 20 cm, 1 30 cm and a 30 cm right angle.  That will allow me to experiment with both mining racks.  And run "the last two" cards on USB 3.0 riser kits.

Tom M

Over the hill?  What hill?  I don't REMEMBER any hill...
A Proud member of the O.F.A. (I've forgotten what that stands for.... ;)

 

 

 

 

Ian&Steve C.
Ian&Steve C.
Joined: 19 Jan 20
Posts: 884
Credit: 5,553,474,371
RAC: 32,065,358

I guess I was unaware that

I guess I was unaware that you bought a second mining style rack. Can you post a link to the new one? What was the reason for moving to the new one? 
 

you still have the same one I’m talking about? Compare my pics to what you have. The same? 
 

which side is the right angle riser for? Over the CPU socket? Or past the other end of the motherboard? Pay attention to which way the “right angle” is being rotated. For over the CPU socket you might need a “left angle” or “270 degree” or whatever nomenclature they want to use, this is a more uncommon setup, I had to buy an expensive riser from direct from China for this application. The more common right angle (commonly used for GPU Vertical mounts in the gamer space) would be ones more suited for past the end of the motherboard. Just make sure you look at the pictures and that the rotation makes sense for what you want to do. Try to visualize it. 

_____________________________________________

Tom M
Tom M
Joined: 2 Feb 06
Posts: 1,119
Credit: 1,943,979,788
RAC: 4,911,374

Ian&Steve C. wrote: I guess

Ian&Steve C. wrote:

I guess I was unaware that you bought a second mining style rack. Can you post a link to the new one? What was the reason for moving to the new one? 

The original listing picture is gone from eBay.  However this is a close version of that picture.

It has two benefits.  1) It takes up less square feet in size.  2) The MB and PSU are on a pull out drawer.

Tom M

Over the hill?  What hill?  I don't REMEMBER any hill...
A Proud member of the O.F.A. (I've forgotten what that stands for.... ;)

 

 

 

 

Tom M
Tom M
Joined: 2 Feb 06
Posts: 1,119
Credit: 1,943,979,788
RAC: 4,911,374

Ian&Steve C. wrote: which

Ian&Steve C. wrote:

which side is the right angle riser for? Over the CPU socket? Or past the other end of the motherboard? Pay attention to which way the “right angle” is being rotated. For over the CPU socket you might need a “left angle” or “270 degree” or whatever nomenclature they want to use, this is a more uncommon setup, I had to buy an expensive riser from direct from China for this application. The more common right angle (commonly used for GPU Vertical mounts in the gamer space) would be ones more suited for past the end of the motherboard. Just make sure you look at the pictures and that the rotation makes sense for what you want to do. Try to visualize it. 

Thank you I missed that 270 degree issue.  I have ordered 4 straight through flat ribbon risers.  Two of the shorter and two of the longer.

I am hoping with them installed I will be able to get past the "stops processing on a different gpu" problem when I run 5 GPUs for more than 24 hours.

Right now I am having trouble with the House getting too hot during the day.  So the EPYC is not running from Noon to 8 pm or so local time.

TomM

Over the hill?  What hill?  I don't REMEMBER any hill...
A Proud member of the O.F.A. (I've forgotten what that stands for.... ;)

 

 

 

 

Tom M
Tom M
Joined: 2 Feb 06
Posts: 1,119
Credit: 1,943,979,788
RAC: 4,911,374

Tom M wrote: Thank you I

Tom M wrote:

Thank you I missed that 270 degree issue.  I have ordered 4 straight through flat ribbon risers.  Two of the shorter and two of the longer.

Just got the two "shorter" ones.  20cm.  Installed, 5 gpus plugged in and 4 gpus showed up.

I have switched from 2 pm to 8 pm or so that the Epyc system is offline.

The longer (30 cm) ribbon risers are due tomorrow.

I hope to get 4 reliable GPUs running then.

Tom M

Over the hill?  What hill?  I don't REMEMBER any hill...
A Proud member of the O.F.A. (I've forgotten what that stands for.... ;)

 

 

 

 

Tom M
Tom M
Joined: 2 Feb 06
Posts: 1,119
Credit: 1,943,979,788
RAC: 4,911,374

Tom M wrote:Tom M

Tom M wrote:

Tom M wrote:

Thank you I missed that 270 degree issue.  I have ordered 4 straight through flat ribbon risers.  Two of the shorter and two of the longer.

Just got the two "shorter" ones.  20cm.  Installed, 5 gpus plugged in and 4 gpus showed up.

I have switched from 2 pm to 8 pm or so that the Epyc system is offline.

The longer (30 cm) ribbon risers are due tomorrow.

Apparently, I ordered the 90 degrees long ones rather than the straight-through version. I have managed to get them installed anyway.  I will try ordering a couple more of the shorter straight through and a long one again later.

The system has booted showing all four flat ribbon cables working.  But until the day cools down I can't run it anymore.

Tom M

Over the hill?  What hill?  I don't REMEMBER any hill...
A Proud member of the O.F.A. (I've forgotten what that stands for.... ;)

 

 

 

 

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.