Does the fan work in an x16 slot? How hot does the card get when hashing wiith no fan?
Either a fan problem or it isn't getting hot enough to need the fan.
It gets to the point where it crashes. I have no control over the cards fans through afterburner when on risers. Put them on a full 16x slot and they function as normal with fans working properly. But 1080ti and 1060 work absolutely fine in these risers. It's almost like the GPU has firmware that stops it being used in a 1x slot.