MSI X570-A Pro motherboard, problems getting +2 gpu for mining

[_javi_]

Thanks for the advice, but its not power related.

Cards are undervolted (bios mod) and combined they consume 240w max while mining.. a 33% increase wouldnt compromise this 850w PSU.

have you measured it at the wall?  have you measured a peak at the wall?  is the power supply brand new? (refurbished psu aren't the best to be mining with... they fail for a reason that isn't always apparent.)

Its a brand new Corsair HX850i (platinum). i'm almost sure its not power related..

[miner29]

I dont bother with cards in the actual slots this present new problems like the 12V supply on the PCI'e slots.

I do highly recommend going to risers on all cards which removes the strain on the bus power.  Each riser gets it power directly from the PSU via either SATA (less optimal) or a 6 pin PCIe connector.  Consider its like 70W each card can draw through the PCIe bus most mobos not meant for mining will have some trouble.  Ie you could be trying to pull 210watts through the bus on top of the PCIe x 8 connection.  So by using riser this issue is eliminated.  It also would put to rest any concerns about wearing out the edge connectors...although i dont think that is an actual issue.

The video cards even is used for a monitor work just fine on a riser on x1 pcie.

And to be clear there is no way to limit what is drawn on the PCIe bus....so best to have it on its on riser.

If you have questions regarding any of what i referencing just ask...happy to explain and post the info.\

None of my gpus are in actual board sockets all are on risers.

[_javi_]

None of my gpus are in actual board sockets all are on risers.

None of mine are in board sockets either. I use flat ribbon cable risers, with molex connector and caps. Btw, I prefer small rigs setups, with 4 gpu max.


I refuse to accept that all my rigs with Sempron140 from 2013 can handle 4 gpus, and this Ryzen 3900X setup on a x570 mobo cant cope with 3.

[miner29]

If its full ribbon flat cable type then you are still pulling power from the pcie bus.  It needs to be the short edge card with just a usb cable to a riser (with its own supply of power from either sata or 6pin pci).  I have some of the ribbon wire ones from Fractal Design (not cheap)..but if its carrying all the pcie card connections then its carrying the power up which only makes it worse (longer distance / more loss).

What you want can be found on amazon under

Mining Powered Riser

Its not that your PSU isnt supplying enough power...its that the mobo's isnt designed to deliver multiples of that at a time.  This is why mining specific boards have additional molex or sata plugs on each end of the PCIe bus to plug psu plugs into for additional power to the bus.  6 gpu boards would have 2 additional plugs and the 13-19 boards would have 2-3 depending on board. 

This is of course assuming thats whats going on...but i am tending that way...because anything over 2 is going to a problem.  Even 2 on some boards is too much.