By the way please check if the one giving less hash is the one on PCI-E 16x slot that you use it for display... it might be busy with routine OS tasks, time to time...
Yes! The one that jumps occasionally is the one being used for display. I did turn off display and it does still jump so I assumed it wasn't that but what do I know
Incorrect shares / GPU errors CAN be caused by faulty risers. Especially if you have identical cards that should be hashing at the same rate. Try changing out the risers, too.
Ok, I gotta buy more risers but perhaps this could be it..
That said, would this change the effective hash rate if the rig is reporting 177.2 in Ethermine?