Question No video output from new GPU. PC goes into startup repair when in crossfire mode

[TazzDevilGaming]

I purchased two AMD Radeon RX 580's for my system (few months apart). The original card works flawlessly on its own. When I plug in the newer card in crossfire, my PC will boot into startup repair mode and not give me any useful options. When I plug the newer card in on its own, I do not get any video output from it whatsoever.
I have Googled my issue multiple times but I seem to only find nVidia / intel solutions.
I am running an AMD Ryzen 5 2600 CPU. The option to plug a video cable into the motherboard is obsolete as these CPU's do not offer dedicated graphics like intel does.
I recently upgraded my PSU from a Corsair CX850w to the new ASUS Thor 1200w in order to power both cards and to have some extra wattage if required hoping that my issue would be fixed, given that ASUS recommends a minimum of 500w for their RX580's.
At this point, I am considering doing a clean install of Windows to see if that fixes any issues such as any driver issues, but before I do that, I hope to get an answer here that will solve my issue.

Specs:
ASUS ROG Strix X470-F Motherboard
ASUS ROG Strix RX580 Graphics Card x2
ASUS ROG Thor 1200w Power Supply
G.Skill AMD 32gb Memory (4x8gb)
AMD Ryzen 5 2600 CPU

 

[rgd1101]

the new gpu doesn't work by itself? try rma the card?

 

[TazzDevilGaming]

the new gpu doesn't work by itself? try rma the card?

I sent the card to ASUS to check/repair. They returned it saying there was no issue with the card.

 

[rgd1101]

is it a new card? or used?

did you tested in the same slot as the working one? same power cable?

 

[TazzDevilGaming]

is it a new card? or used?

did you tested in the same slot as the working one? same power cable?

It's new. Have tested it in both 16x and 8x slots with both different and same power cables that I use for the original card. Tried everything I could think of. I'm totally stumped at this point.

 

[TazzDevilGaming]

I have decided to try a fresh installation of Windows to see if that fixes my issue.
So far it is working, but I am yet to update any drivers. I keep getting an alert from AMD Catalyst that my display drivers have crashed and recovered. It appears my computer has frozen, so I'm gonna restart to see if it fixes the issue.

 

[TazzDevilGaming]

All seemed to be running fine, then all of my screens turned off. Pressed the restart button and loaded back in. Now attempting to update video card drivers.

 

[rgd1101]

check the bios version on the 2nd gpu? still think there an issue with it

 

[TazzDevilGaming]

I did a full reinstall of the OS. Downloaded the latest video card drivers. The computer has been running fine for the past 6 hours. Awaiting the latest Windows update to reveal itself. I have done a 3DMark test and only getting scores of around 4,500.
I don't know what the initial problem was, but I seem to have fixed it (for now). Will keep this thread updated.

How do I check / update GPU BIOS?

 

[rgd1101]

try gpuz https://www.techpowerup.com/gpuz/