Author

Topic: Separate power supply for GPU's? (Read 224 times)

newbie
Activity: 31
Merit: 0
January 04, 2021, 06:01:53 PM
#10
i have same connector for psu

3 PSU * 750W EVGA Silence for 9/10 cards: 1440W / 3

my rig https://twitter.com/i/status/1342965540038582272
full member
Activity: 602
Merit: 106
January 04, 2021, 05:42:52 PM
#9
Hey Everyone,

I am building a GPU miner and decided well into the project that I was going to add a few more GPU's than originally planned.

Unfortunately I already have a power supply installed and I had to mod the case a bit to make it fit. I can't return it for a larger one.


I do have a 12 volt 40 amp power supply available. Could I run the power to the GPU's 8 pin connector from a second power supply without trouble?

What do you all think?

Thanks.

S.

I did the exact same thing when my I was in the mining game in 2017. My MOBO (and everything that was on it) got power from normal 750w ATX PSU. Now, the 6 R9 290 cards got their 8+6 pin from a server PSU. I bought mine from parallelminer.
full member
Activity: 1275
Merit: 141
January 04, 2021, 01:39:46 PM
#8
Yes I did this back in the 2014 days alot. PSUs back then were expensive and GPUs required more power so it was very common practise. However there are a few things to keep in mind.

You cannot mix any of the +12V together. So don't plug in PCIe to one PSU while into the other PCIe port on the same GPU plug in to the other GPU. These days most GPUs have 1 PCIe so it shouldn't be a problem.

However the +12V for the riser should also come from the same PSU to be safe. Normally the +12V going into the GPU from the riser is seperate from the +12V going into the PCIe slot. I've measured this myself with a multimeter.

The way people burned PSUs and Mobo's back in 2014 was because they attached +12V to one PSUs to the ribbon risers and +12V from another PSU to the motherboard and there was current feedback and it destroyed the motherboard typically. However with USB risers it shouldn't be much of an issue.

Another thing to do is make sure to ground the PSUs together. Just connect the grounds together. And make sure the 2nd PSU always has a load on in case the main PSU shuts off for some reason.


Thank you!

If I am understanding correctly: One PSU for the motherboard and drive. A second PSU powering the PCIe cards and the GPU's.

Am I pointed in the right direction?

Thanks again.

Yes but the mobo psu if it has capacity can power gpu/riser....just dont mix psu2 with and card/riser that goes to psu 1.

As the song goes....you gotta keep’em separated!

So if you have a 1000watt on mobo you can run several cards/risers off it and the mobo...then the other cards and their risers would all go to psu2.    The only time it would be different is with a h110 mining board that has 3 psu hook ups built on it.
newbie
Activity: 14
Merit: 2
January 04, 2021, 01:33:55 PM
#7
Yes I did this back in the 2014 days alot. PSUs back then were expensive and GPUs required more power so it was very common practise. However there are a few things to keep in mind.

You cannot mix any of the +12V together. So don't plug in PCIe to one PSU while into the other PCIe port on the same GPU plug in to the other GPU. These days most GPUs have 1 PCIe so it shouldn't be a problem.

However the +12V for the riser should also come from the same PSU to be safe. Normally the +12V going into the GPU from the riser is seperate from the +12V going into the PCIe slot. I've measured this myself with a multimeter.

The way people burned PSUs and Mobo's back in 2014 was because they attached +12V to one PSUs to the ribbon risers and +12V from another PSU to the motherboard and there was current feedback and it destroyed the motherboard typically. However with USB risers it shouldn't be much of an issue.

Another thing to do is make sure to ground the PSUs together. Just connect the grounds together. And make sure the 2nd PSU always has a load on in case the main PSU shuts off for some reason.


Thank you!

If I am understanding correctly: One PSU for the motherboard and drive. A second PSU powering the PCIe cards and the GPU's.

Am I pointed in the right direction?

Thanks again.
legendary
Activity: 3808
Merit: 1723
January 04, 2021, 12:52:15 PM
#5
Yes I did this back in the 2014 days alot. PSUs back then were expensive and GPUs required more power so it was very common practise. However there are a few things to keep in mind.

You cannot mix any of the +12V together. So don't plug in PCIe to one PSU while into the other PCIe port on the same GPU plug in to the other GPU. These days most GPUs have 1 PCIe so it shouldn't be a problem.

However the +12V for the riser should also come from the same PSU to be safe. Normally the +12V going into the GPU from the riser is seperate from the +12V going into the PCIe slot. I've measured this myself with a multimeter.

The way people burned PSUs and Mobo's back in 2014 was because they attached +12V to one PSUs to the ribbon risers and +12V from another PSU to the motherboard and there was current feedback and it destroyed the motherboard typically. However with USB risers it shouldn't be much of an issue.

Another thing to do is make sure to ground the PSUs together. Just connect the grounds together. And make sure the 2nd PSU always has a load on in case the main PSU shuts off for some reason.
newbie
Activity: 14
Merit: 2
January 04, 2021, 11:55:05 AM
#4
Thanks for the input.


I am not entirely understanding  Rduffy 's warning.

I am considering  running all of the  8 pin power connectors from a separate power supply.  If I do that,  should I  disconnect the 12v from the main power supply that goes to the risers?  Or,  should I connect the riser power to the new 12v power supply?

Thanks again.
member
Activity: 1201
Merit: 26
January 04, 2021, 07:22:42 AM
#3
You can use 2 PSU, no problem
You should use this piece:



It's called add2psu, it's cheap and easy to find on china sellers, you will connect to your main PSU and will turn on when your main psu is turned on, to running together


Yes also dont mix +12v to 2nd psu. it can cause weaker psu burn. Simply feed your risers and 8 pin together from 2nd psu.
legendary
Activity: 2366
Merit: 1408
January 04, 2021, 06:17:41 AM
#2
You can use 2 PSU, no problem
You should use this piece:



It's called add2psu, it's cheap and easy to find on china sellers, you will connect to your main PSU and will turn on when your main psu is turned on, to running together

newbie
Activity: 14
Merit: 2
January 03, 2021, 07:07:51 PM
#1
Hey Everyone,

I am building a GPU miner and decided well into the project that I was going to add a few more GPU's than originally planned.

Unfortunately I already have a power supply installed and I had to mod the case a bit to make it fit. I can't return it for a larger one.


I do have a 12 volt 40 amp power supply available. Could I run the power to the GPU's 8 pin connector from a second power supply without trouble?

What do you all think?

Thanks.

S.
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