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Topic: gpu with two different psu (Read 399 times)

newbie
Activity: 284
Merit: 0
June 20, 2018, 10:14:00 AM
#21
If both of your PSUs are working normally, you can do that by "paperclip technique". To prevent any problem that may happen, you shouldn't do that. GPU draw power from both 8-pin/6-pin connector and riser, so if a PSU is down, you may kill your GPU. If you have a rig of 8 x GPUs powered by 2 PSUs, you can power your mainboard and 4 GPUs with the first PSU and 4 remaining with the second one
newbie
Activity: 17
Merit: 0
June 20, 2018, 07:30:13 AM
#20
I speak from personal experience.

DON'T do this.

we have an 8 GPU mining rig and we were using 2 power supply.
usually we make sure that the PSU powering the PCIE of the GPU also powers its risers.
but we messed up on one GPU and it's riser ended up being powered up by the second PSU.
what happened was the PSU powering the PCIE of the GPU died. so the only place the GPU can draw power
was from the riser. good thing we noticed quickly because when we checked the riser was REALLY HOT.
if it was left uncheck it could have started a fire. so please don't do this.

 Smiley
full member
Activity: 392
Merit: 137
June 20, 2018, 07:11:50 AM
#19
Hi

If I connect a gpu to a cable pcie of a psu and the riser with a cable of a different psu, can it be a problem?

Apologies for my bad command of english.
you shouldn't do that. every GPU/riser pair should be powered from one common power source.
Why do you give advice and at the same time do not understand the subject at all? This is a post for post? Go to another branch! My rigs have been working for several years without problems from several power supplies. The motherboard and riser are powered by ATX power supply and additional power supply of GPU of two neighboring rigs is connected to powerful server power supply.
legendary
Activity: 2618
Merit: 6452
Self-proclaimed Genius
June 20, 2018, 04:31:40 AM
#18
From an IT point of view it should not be a problem as long as you have connected in series the 2 Psu-s. Connecting in series mean to unite both psus with the green cable.
Please do not describe the tool that simultaneously starts 2 PSUs as "series" because it may cause some misunderstanding and might cause an accident.
I appreciate all your comments, the truth is that it remains unclear, but now it is not as simple as I thought.
Here's a conclusion:
It's unclear to you because the consensus here seemed to be divided to yes or no, but most of those who said yes are those who aren't sure themselves or just google searched the term for you.
I just found 3 persons who are using unrelated terms which strongly suggest that those must have been wrong.

These are the most valid answers so far:
-snip-
So can you? Yes.

Should you? I would rather not but I like to keep everything a bit organized. It would likely be fine for the short term but if it can be remedied in the long term best to get them on the same PSU.
Can you.... Yes

Should you.... NO!!

-snip-
newbie
Activity: 48
Merit: 0
June 19, 2018, 06:39:13 PM
#17
Hello everybody,
         Greetings!

                   I am writing the reply of some one's post about the question "If I connect a gpu to a cable pcie of a psu and the riser with a cable of a different psu, can it be a problem?" which is not so much clear question eventhough I would like to try in simple and short as possible as I can.
In my guess, he would like to make a large GPU mining Rig(eg: 9 GPUs) in a single motherboard at that time he should use two Power supply Unit (PSU) for a single motherboard but safety considerations and procedures should follow for the best result like better to use good quality PSU and should use T2PSU adapter of high quality which connects the two PSU in series with the motherboard simultaneously.It does not matter you can use PSU of two different power capacities.At this situation no problem you can do it.I hope you understand.Thank you.

Depending on the GPUs and their power consumption you have several options.

The Asus board mentioned above works, so does the Colorful b250 pro mining board with dual 24 pin PSU connections on the board.

Add2PSU is also an option.

Best would be to get a cheap small PSU for the motherboard and a server PSU like is used for ASICs. Get the PSU and a breakout board for your 6/8 pin PCIe cables. Depending on your GPUs you will need to use 2-3 per card. Breakout boards have varying numbers of PCIe outputs, common to have 22. This allows you to do 7 cards if it is 3/card. If you need to get to 9 cards just use a main PSU that gives you enough to run two more cards and the motherboard. If you are using lower power cards with a single 6 or 8 pin PCIe then run 11 from the server PSU and 1 from the main PSU.
jr. member
Activity: 59
Merit: 4
June 19, 2018, 06:00:35 PM
#16
NEVER Do that unless both PSUs ground are joined together. If you use the paper clip method, you will burn all your GPUs.

You can do it with ADD2PSU, or if you have an ASUS B250 mining motherboard, or any dual PSU adapters
newbie
Activity: 20
Merit: 0
June 19, 2018, 04:10:29 PM
#15
Hello everybody,
         Greetings!

                   I am writing the reply of some one's post about the question "If I connect a gpu to a cable pcie of a psu and the riser with a cable of a different psu, can it be a problem?" which is not so much clear question eventhough I would like to try in simple and short as possible as I can.
In my guess, he would like to make a large GPU mining Rig(eg: 9 GPUs) in a single motherboard at that time he should use two Power supply Unit (PSU) for a single motherboard but safety considerations and procedures should follow for the best result like better to use good quality PSU and should use T2PSU adapter of high quality which connects the two PSU in series with the motherboard simultaneously.It does not matter you can use PSU of two different power capacities.At this situation no problem you can do it.I hope you understand.Thank you.
newbie
Activity: 48
Merit: 0
June 19, 2018, 03:26:27 PM
#14
The question here is not about a system with two PSUs but about splitting power within a single GPU across two PSUs. 6/8 pin(s) on one PSU and the riser power on the other.

Ideally they would be on the same supply so that fluctuations in power are equal. Whether single rail or multiple rails the ground is common. That said, on the GPU board the components are isolated so the 12V and 5V voltage ripple should not cause any interference. That said, there is the possibility of unexpected things happening if power were to be cut to one psu and not the other while running. Mostly it would just shut the GPU down.

So can you? Yes.

Should you? I would rather not but I like to keep everything a bit organized. It would likely be fine for the short term but if it can be remedied in the long term best to get them on the same PSU.
legendary
Activity: 3318
Merit: 1247
Bitcoin Casino Est. 2013
June 19, 2018, 02:37:10 PM
#13
I appreciate all your comments, the truth is that it remains unclear, but now it is not as simple as I thought.

From an IT point of view it should not be a problem as long as you have connected in series the 2 Psu-s. Connecting in series mean to unite both psus with the green cable.

Here is a video of how to do it, anyway don't try this without the help of an IT professional.

https://www.youtube.com/watch?v=PPUQjWDSddE
jr. member
Activity: 87
Merit: 2
June 19, 2018, 11:54:55 AM
#12
I appreciate all your comments, the truth is that it remains unclear, but now it is not as simple as I thought.
sr. member
Activity: 350
Merit: 250
June 19, 2018, 04:54:23 AM
#11
Hi

If I connect a gpu to a cable pcie of a psu and the riser with a cable of a different psu, can it be a problem?

Apologies for my bad command of english.


Don't do that, unless your psu are hybrid support. read and educate yourself about it on google first. For starters, this seems highly unsafe to me.

Edit: I had googled about powering your mobo with different gpus and powering your gpu with different, and you were advised to not.
member
Activity: 266
Merit: 50
June 19, 2018, 04:48:39 AM
#10
Don't do that!
If you really need to do this (don't!) make sure you use the some power plug for both psus. The ground has to be common.
Why not?
You should imagine if using more than 10 GPUs on a single motherboard, of course you can use more than one PSU, almost all miners use more than one PSU for mining rigs.
jr. member
Activity: 77
Merit: 1
June 18, 2018, 10:24:23 PM
#9
There's no problem, and it shouldn't be a problem.
newbie
Activity: 154
Merit: 0
June 18, 2018, 07:59:50 PM
#8
As long as your PSUs are good quality and 80+ certificate, that's no problem. Because the theory is : GPU and riser can take power from any PSU.
As long as GPUs and risers get their power, it can be use by motherboard. No meter where power come.
And remember it's very important, PSUs must power on at the same time.
newbie
Activity: 44
Merit: 0
June 18, 2018, 02:50:25 PM
#7
Don't do that!
If you really need to do this (don't!) make sure you use the some power plug for both psus. The ground has to be common.
sr. member
Activity: 588
Merit: 335
Steady State Finance
June 18, 2018, 12:37:10 PM
#6
If I connect a gpu to a cable pcie of a psu and the riser with a cable of a different psu, can it be a problem?

Nothing to worry about it. You were only needed to keep the 2nd PSU keep turn on. So jump-start technique with paper clips will be better than another tool that will delay the second PSUs turning on.
jr. member
Activity: 59
Merit: 11
June 18, 2018, 10:18:13 AM
#5
1. Why would you need to split it?
2. What kind of PSUs are we talking about? High quality or crap? (HQ PSUs are built "smarter" at detecting/regulating how things are connected to it)

Typically, the same PSU should power the riser AND the GPU connected to it. However, most of the time, the problems you see with fried connectors comes down to cheap power adapters being used. If you can avoid it, don't use any type of power adapter (SATA to 6-pin, for example). Just go straight from the PSU to the device you are power with the cables that came with the PSU. Also, be sure that both PSUs power up at the same time. If your BIOS is set to power on after power loss (AC -> ON), then you can use a simple power strip to do this part (just connect both the a power strip that has a power switch and use that to power on your rig).
jr. member
Activity: 60
Merit: 3
June 18, 2018, 09:04:54 AM
#4
Haven't tried it, but from what I know that's a big NO.
jr. member
Activity: 238
Merit: 3
June 18, 2018, 08:52:07 AM
#3
Hi

If I connect a gpu to a cable pcie of a psu and the riser with a cable of a different psu, can it be a problem?

Apologies for my bad command of english.
you shouldn't do that. every GPU/riser pair should be powered from one common power source.
member
Activity: 266
Merit: 50
June 18, 2018, 08:38:41 AM
#2
no problem, as long as you are correct in installing it and both PSUs don't have a problem if you want to install both PSUs simultaneously use add2PSU or use paperclip technique.
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