Are You guys on windows 7 with those 8th gpu problems? It won't work... You need win10 or linux.
Sure mate Win10 x64 EnterpriseMy problem is not 8th GPU: it's the 5th card that makes my rig enter boot loop ONLY when one of those 5 cards is connected to 16x slot!
So if I skip the 16x slot I can add and run 7 cards easy and clean...Weird
!Tried to boot into safe mode with it? You'll have to force safe boot by booting with your 7 cards and restart with safe mode enabled on next run.
Force shutdown > plug in 8th card > boot into safe mode (if it works)