Model Number:   VCGGTX10603XGPB-OC-BB   PNY GTX 1060 3GB XLR8 VERSION

Yesterday,  I tore it down so that they were just two cards running on the 1000 PSU. I ran it all day with a power limit of 70 and memory clock +476  individually on both cards.
I added the third card when I went to bed and woke up to a frozen screen again.  So, I replaced the riser on the third card..

Six hours ago, I attached two more cards to the 1000 PSU for 5 total. But this time I placed settings for all five at power limit 70, memory clock + 476, core +46..

I also  reinstalled  Nvidia drivers to the latest,  version     384.94

It's been running fine for the last six hours with temperatures  on the cards between 66 and 69°C. I don't have any fans on them and the window slightly open. It's been 96°Fahrenheit out today. air-conditioners in the other room.

471 W total.

I guess I'll let it run through the night and see what happens. tomorrow add the sixth card off the 850 PSU.

So I'm not sure if was a riser or settings. I just hope it's working good now..