Conversations about your/my setup

Ian&Steve C.
Ian&Steve C.
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Tom M wrote: How do you

Tom M wrote:

How do you avoid straining a single 1600 watt PSU with a 7 ribbon cable GPU setup?

You can't split the top side power supplies because of various voltage differences between two 1600 watt psu's.

Tom M

I only ever ran one multi-GPU system off a single (EVGA) 1600W PSU. that was my watercooled 7x2080 system.

each GPU was plugged directly into the board, but a ribbon riser setup would be functionally identical with power to the slot coming from the motherboard (and not external power like you would see with USB risers).

each GPU has 1x8-pin and 1x6-pin power connection. would could be serviced by a single power lead from the GPU (8+6-pin), and the 1600W PSU has connections for 9x such cables. I had to buy a couple extras from ebay since the PSU only came with 5x 8+6-pin and 4x 8-pin (no pigtail).

then it was necessary to power limit each GPU to just 185 watts in order to keep total system power consumption acceptable, with a 200W CPU. this wasn't too bad of a power limit for an RTX 2080, down from the default 215W.

 

with ~300W RTX 3080/Ti cards, I wouldn't run more than 4 on a single 1600W PSU.

 

my other two multi-GPU systems (7x and 5x) are both running with the motherboard + 1GPU powered by a single 1000-1200W PSU, and the other GPUs powered by 2x 1200W PSUs with the GPUs split between them.

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Ian&Steve C.
Ian&Steve C.
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if you want to run dual PSUs,

if you want to run dual PSUs, you should get an adapter like this to power up the non-MB PSU when the main system is powered on.

 

it will send the signal to power on the secondary PSU, so you can use the PCIe and other power connections from it. it will also shut down with the prime PSU when the system is powered up.

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Tom M
Tom M
Joined: 2 Feb 06
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Ian&Steve C. wrote: my other

Ian&Steve C. wrote:

my other two multi-GPU systems (7x and 5x) are both running with the motherboard + 1GPU powered by a single 1000-1200W PSU, and the other GPUs powered by 2x 1200W PSUs with the GPUs split between them.

It sounds like you are no longer using flat ribbon cables but instead are using the usb3 riser kits? Then those machines are never going to run Gpugrid?

Tom M

A Proud member of the O.F.A.  (Old Farts Association).  Be well, do good work, and keep in touch.® (Garrison Keillor)  I want some more patience. RIGHT NOW!

Tom M
Tom M
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Ian&Steve C. wrote:with

Ian&Steve C. wrote:

with ~300W RTX 3080/Ti cards, I wouldn't run more than 4 on a single 1600W PSU.

What I am bothered by is how warm the PSU power cable gets when I run all 4 off one 1600 watt PSU.

I suppose I could just ignore it until the power cord melts?

Tom M

A Proud member of the O.F.A.  (Old Farts Association).  Be well, do good work, and keep in touch.® (Garrison Keillor)  I want some more patience. RIGHT NOW!

Ian&Steve C.
Ian&Steve C.
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Tom M wrote: Ian&Steve C.

Tom M wrote:

Ian&Steve C. wrote:

my other two multi-GPU systems (7x and 5x) are both running with the motherboard + 1GPU powered by a single 1000-1200W PSU, and the other GPUs powered by 2x 1200W PSUs with the GPUs split between them.

It sounds like you are no longer using flat ribbon cables but instead are using the usb3 riser kits? Then those machines are never going to run Gpugrid?

Tom M

what made you come to that conclusion? All of my systems are still on ribbon risers. As they always have been, I don’t run GPUGRID often due to task availability and my focus on Einstein right now, but I do still run GPUGRID occasionally.
 

I haven’t used USB risers since running SETI. 

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Ian&Steve C.
Ian&Steve C.
Joined: 19 Jan 20
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Tom M wrote: Ian&Steve C.

Tom M wrote:

Ian&Steve C. wrote:

with ~300W RTX 3080/Ti cards, I wouldn't run more than 4 on a single 1600W PSU.

What I am bothered by is how warm the PSU power cable gets when I run all 4 off one 1600 watt PSU.

I suppose I could just ignore it until the power cord melts?

Tom M

youll have to be more quantitative. How hot is hot? Unless it’s burning your hand hot, it’s not going to melt. 
 

are you using a sufficiently sized power cord for ~1400W continuous load? The 1600W PSU should have come with a beefy cable. 

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Tom M
Tom M
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Ian&Steve C. wrote: what

Ian&Steve C. wrote:

what made you come to that conclusion? All of my systems are still on ribbon risers. As they always have been, I don’t run GPUGRID often due to task availability and my focus on Einstein right now, but I do still run GPUGRID occasionally.

I assumed both the Pcie slot and the top power plugs had to be on the same PSU.

You disabused me of that in another thread.

I have moved 3 of the gpus top power plugs onto the secondary 1600 Psu and moved the modular ribbon cable onto the primary 1600 watt psu (so Pcie is not getting it from two PSU's).

I am not sure I have ever split a GPU between two PSU's on the top power plugs..

Tom M

A Proud member of the O.F.A.  (Old Farts Association).  Be well, do good work, and keep in touch.® (Garrison Keillor)  I want some more patience. RIGHT NOW!

Tom M
Tom M
Joined: 2 Feb 06
Posts: 6586
Credit: 9662198318
RAC: 2744234

Ian&Steve C. wrote: Tom M

Ian&Steve C. wrote:

Tom M wrote:

Ian&Steve C. wrote:

with ~300W RTX 3080/Ti cards, I wouldn't run more than 4 on a single 1600W PSU.

What I am bothered by is how warm the PSU power cable gets when I run all 4 off one 1600 watt PSU.

I suppose I could just ignore it until the power cord melts?

Tom M

youll have to be more quantitative. How hot is hot? Unless it’s burning your hand hot, it’s not going to melt. 
 

are you using a sufficiently sized power cord for ~1400W continuous load? The 1600W PSU should have come with a beefy cable. 

Both 1600 watt PSU's come with beefy cables.  Just got done moving 3 out of 4 gpu top power plugs onto the 2nd PSU and moving the modular powered cable onto the primary psu.

And now none of the power supply cords are warm at all :)

Tom M

A Proud member of the O.F.A.  (Old Farts Association).  Be well, do good work, and keep in touch.® (Garrison Keillor)  I want some more patience. RIGHT NOW!

HAL
HAL
Joined: 9 Mar 20
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I just ventured into the

I just ventured into the water cooling arena today. I installed an EVGA CLC 240 for the main computer for this project. The CPU is Ryzen 7 1700 @ 3.2 GHz. Before as a test, I ran 10 threads under Linux Mint for Einstein@Home and I recorded a CPU temp of 53 deg C. After removing the fan cooling system and installing this new system, the CPU temp went down to 41 deg C. I then bumped up to 15 threads and it actually went down to 39 C - presumably because the pump ran faster and was able to achieve more cooling. Might play with the clock speed some more now. So very pleased with it.

 

I told all my friends I could teach them how to be funny, but they all just started laughing at me.

Keith Myers
Keith Myers
Joined: 11 Feb 11
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Since pumps normally should

Since pumps normally should be run at full speed, you should just plug the pump header into a uncontrolled 12V header port.  As long as you can handle the noise increase from the rad fans you will achieve the best cooling that way.

 

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