It is related with 1 GPU. Of of your gpu can not handle memory OC settings. You should lower memeory OC and try to fine sweet spot.
I was with 2 gpu Asus rog strix rx570 4gb and happened to crash randomly, problem solved when I installed only the pure GPU drive.
I added a 3rd gpu also asus rog strix and now they do not crash, but the 3rd GPU drops the hashrate to 00.00 randomly.
I'll lower the memory clock. It is? I'll run some tests throughout the day.
@edit
Curiously, the 3 GPUs use the same settings. How can one just drop the hashrate?
ETH hashrate is 00.00
https://i.imgur.com/7Lm160n.jpgZcash the hashrate is normal (low because it is without biosmod).
https://i.imgur.com/RQ8BqCI.jpg@edit2
I put a GPU straight on the motherboard, without using the riser. So far it's normal. I will continue monitoring.
http://prntscr.com/hl6qzp
