Not much to offer except reset everything in case you missed something . . . clear CMOS, load basic mobo defaults, reinstall the chipset drivers and perhaps VLC. But these seem as ineffectual as swapping the power cables on the vid cards lol.
Perhaps more basics . . . when testing non-SLI, did you physically remove whichever unused card from its slot? Did the primary card fail when run non-SLI (not clear)? Can you get either card into the other slot by pulling the other card out of its slot?
Cards can't be moved unless i strip the loop, and considering it took about 10hrs to build it yesterday, i really dont want to do that. i cant move the slots they are in for the same reason.
runing 2nd gpu atm, 1st is still being detected by windows but disabled in nvidia control panel.
gonna look into bios flashing the ist card from the rom on on the second. problem is. i dont know if i can boot from my secondary card in the 5th PCIe slot, so if i brick it, i will have to strip the blocks off and replce with standard air vooling just to un brikck, then will have to rebuild loop again.