What motherboard and PSU(s) are you using? Other than a few dedicated mining motherboards most won't run with more then 3-4 GPUs maybe 5.... some can do more then that but they are often a pain in the arse to deal with. At this point we don't deal with motherboards that are not specific dedicated mining mobos, the hassle and headache is not worth it otherwise.
8 PNY GTX 1060 3 GB MPN: VCGGTX10603XGPB-OC-BB XLR8 Edition
ASUS PRIME Z270-A LGA 1151
Windows 10
EVGA SuperNOVA 1000 G3 powering five cards and the risers, motherboard and SSD
EVGA 850 BQ just powering three of the cards
At this point, I have reloaded the latest Nvidia drivers multiple times. I reinstalled Windows 10. I've updated the bios and checked settings -- I have another rigged with the same exact specs except the cards are not the XLR8 VERSION. i'VE REINSTALLED msi AFTERBURNER.
-I've run only four cards on the PSU 1000 just fine. Changed the riser and card that was disabled -- of course that new riser could be bad also.
-I've run the new card in riser, and three of the cards work fine on the 1000, and 4 other cards on a different PSU. Still got triangle error in device manager on one card.