All warranties of AMD stuff need to go through the manufacturer. I doubt that the retail shop that sold it would replace it. They could see that you have a modded bios but in my experience they will RMA the card.
That's comforting. Thanks!
I will still go to the shop tomorrow and will claim that the risers they sold me damaged one of the cards (which is a possibility)
I'm not comfortable with the SAPPHIRE TRIXX setting everything to ZERO on it's own even with the good cards.. I might just rebuild the whole setup and reinstall windows and disable all updates etc..
Things are going haywire and I don't have control over what's going on as I did before