I actually have tried 3 different risers for this card, now that I think about it.  The 3rd being a riser that is running just fine in another rig, I really dont think its a riser issue.  Also I've tried powering the card in question with each of the two PSU's in the rig, no difference.  I swapped out the Add2PSU device thinking maybe that is somehow causing a weird power issue...no effect.

I just think its really damn odd this card's memory runs over 200mhz higher than the other 5 1070 ti's at the same exact power level.