Well as I was at an impasse as to making any further changes to the rig. I just restarted it once, after a quick mining failure. Then it went through a windows/NVidia driver #$%^ storm 
....... and now I am looking into SMOS again.
I was able to get SMOS up and running. The third card was dragging in hash rate, then would crash. I replaced the riser, the same thing happened. I then just ran two cards and the hash rate was fine. I decided to move the 3 card down a slot, and unfortunately it kept doing the same.
I'm starting to think it might be the board as it is showing symptoms similar to what others have seen. Trying a new motherboard/processor tomorrow.
SMOS is pretty slick, certainly a bit more too learn, but doesn't look too daunting. Fortunately I was able to get up to a testing point to see that there still may be a hardware issue that was lurking.
Switching over to a Gigabyte GA-Z270-HD3 and an i3 processor tomorrow.
....... and now I am looking into SMOS again.I was able to get SMOS up and running. The third card was dragging in hash rate, then would crash. I replaced the riser, the same thing happened. I then just ran two cards and the hash rate was fine. I decided to move the 3 card down a slot, and unfortunately it kept doing the same.
I'm starting to think it might be the board as it is showing symptoms similar to what others have seen. Trying a new motherboard/processor tomorrow.
SMOS is pretty slick, certainly a bit more too learn, but doesn't look too daunting. Fortunately I was able to get up to a testing point to see that there still may be a hardware issue that was lurking.
Switching over to a Gigabyte GA-Z270-HD3 and an i3 processor tomorrow.