How would you connect 2 PSUs?

[autoturn]

I have 4 GPUs for mining:
ASUS RTX 3080 TUF OC 10G
Sapphire Vega 64 Limited Edition 8GB
2 x Gigabyte RX 580 8 GB
These 4 GPUs would be connected to a motherboard Gigabyte B460 HD3 that has 5 PCIe slots, using risers.

I have 2 PSUs available that I would like to use in the rig:
INTER-TECH Power Supply Great Wall M1200 (1250 W)
Corsair RM 750 W
The main question that bothers me is how I can connect both PSUs to power the rig since one is not enough and the motherboard only has a 1x 24 pin slot, 1x CPU power slot, etc... Have you maybe used 2 PSUs similar to these above?

How would you do it? Thanks.

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[philipma1957]

I have 4 GPUs for mining:
ASUS RTX 3080 TUF OC 10G
Sapphire Vega 64 Limited Edition 8GB
2 x Gigabyte RX 580 8 GB
These 4 GPUs would be connected to a motherboard Gigabyte B460 HD3 that has 5 PCIe slots, using risers.

I have 2 PSUs available that I would like to use in the rig:
INTER-TECH Power Supply Great Wall M1200 (1250 W)
Corsair RM 750 W
The main question that bothers me is how I can connect both PSUs to power the rig since one is not enough and the motherboard only has a 1x 24 pin slot, 1x CPU power slot, etc... Have you maybe used 2 PSUs similar to these above?

How would you do it? Thanks.

I would ask the question in the altcoin section as you won’t direct mine btc with gpus.

you could mine on nicehash and indirectly get btc that way.

Now a proper setup to a riser can isolate the second psu from the first one.

I will ask mods to move this to right section.

[miner29]

if a gpu is powered by a psu …. its riser needs to be powered by the same psu.

Use a dual psu Y cable (under $10 on amazon) to sync the psus so they start and stop together.  

Risers are the only way to do this.  Just keep gpu/riser on same psu.  

And all mother board connections from a single psu.  

ive had up to 3 psus on a single large rig.

[JayDDee]

It should be obvious but I would add that the big PSU should power the motherboard and the 2 biggest GPUs.
I would also recommend powering the GPU in the primary x16 slot with the same PSU as the motherboard, it allows
that GPU to be directly connected to the motherboard if you're short on risers.
And I'll repeat how critical it is to isolate the GPUs powered by the secondary PSU from the motherboard with risers.

[STSMiner]

Do it right the first time and don't cut corners to save a buck or three.

https://www.gpuminingresources.com/p/psu-cables.html

Example below when using GPU's that have 2 or 3 power ports on them, the correct way is shown on the right in the image.

[adaseb]

You sure you can’t connect the riser to the other PSU? Been years since I’ve done this but from what I remember the power to the GPU coming from the riser is not directly connected to the PCIe power connector at the top. You can take a multi meter and verify this.

Unless some of the newer GPUs are different then the older r9 280x that I had to have a dual PSU option for.

Oh, I also made sure both the PSUs were grounded together.

[STSMiner]

Cross feeding power to your GPU's via two PSU's should never be done !

If one of the PSU's develops a fault and stops working for some reason because one of the connectors / cables has melted and started a fire or one of the GPU's has a burn out (catches fire) it's going to cause a feedback loop to all other devices and kill them if your unlucky.

If you want to mix and match this you risk back-feed/run-away into the motherboard and will probably break stuff and/or set your house on fire too.

Power your devices the right way the first time.

See note 1 in the article below.

https://forum.zcashcommunity.com/t/the-facts-about-gpu-mining-electrical-specifications/19468

"New risers have NO power connection to the mobo, only data via the USB cable. They make their own 3.3V on the riser from the 12V rail. You NEED to test your risers to confirm this. Ultimately you are responsible for building your rig in a safe and reliable way. Not me, or any other person on this forum. Having said that, each GPU should be powered from one PSU (both riser and 8 or 6 pin connector)."

[FP91G]

I have 4 GPUs for mining:
ASUS RTX 3080 TUF OC 10G
Sapphire Vega 64 Limited Edition 8GB
2 x Gigabyte RX 580 8 GB
These 4 GPUs would be connected to a motherboard Gigabyte B460 HD3 that has 5 PCIe slots, using risers.

I have 2 PSUs available that I would like to use in the rig:
INTER-TECH Power Supply Great Wall M1200 (1250 W)
Corsair RM 750 W
The main question that bothers me is how I can connect both PSUs to power the rig since one is not enough and the motherboard only has a 1x 24 pin slot, 1x CPU power slot, etc... Have you maybe used 2 PSUs similar to these above?

How would you do it? Thanks.

I have used these synchronizers.
It's called the Molex 24-pin ATX PSU Trigger Synchronizer.
You connect the first power supply to the motherboard, and connect the Molex connector from it to this synchronizer.
Plug the 24-pin of the second block into this synchronizer and both power supply blocks will turn on and off simultaneously.

There is the same model with a sata connector.