Quote from: iom on January 12, 2017, 10:18:23 PM

I don't know about that video, but i use first psu to powered 3 usb risers and 3 cards, and secont PSU to powered more 3 usb risers and 3 cards, and rig working fine more than a 3 months.

Quote from: joaocha on January 13, 2017, 01:04:12 AM

Power Gpu + Riser with same Psu, if you do diferent them this i ill have problems,

All of my 7 rigs are using 3 Psu each, 1 for mobo + hd , and 2 750w for the Gpus

I'm starting to think this is the solution: to plug in the secondary PSU to the powered risers, instead of plugging the primary PSU into the risers. But, I'm still worried about frying my motherboard .

I'm using USB risers: https://www.hashratestore.com/wp-content/uploads/2014/01/20140130_121606-500x354.jpg Are these the ones you use in your systems?

Can anyone confirm that the USB cables are only used for data, not power in these risers? If so, this solution can't possibly fry the motherboard, right?

UPDATE:

Found this post on the ethereum forum:

Quote

The USB risers are power-isolating in the sense they do not have power lines from the motherboard - power is only from the child-side riser power. The idea that you should use the same PSU for mobo and risers is TOTALLY backwards for USB-type risers - it's old info from non-cut/non-powered era. You're better off using the same PSU for a given riser/GPU, since what is the riser really doing here? Powering the GPU... why would you choose to power the GPU with multiple PSU for no reason?

How do you ground 2 PSUs together? Use a dual PSU cable (e.g. power-on lead and ground y-connector), or run any ground lines between the 24pin

Also, I found this post:

Quote from: Bazelak on April 29, 2016, 05:56:45 AM

I have a few USB powered risers. I tested it. The +12V is not taken from the motherboard, it is only from the SATA +12 connector. So you can connect it to either main or the secondary PSU.

UPDATE 2:

I tried to connect the USB powered risers + GPU power to the secondary PSU, and nothing changes: the secondary psu powers on for 1 second then shuts off, with the primary PSU working fine powering 2 GPUs.