At stock clock settings it works without problems.
But how should I find out which cards could I overclock how much, when always GPU 2,3 nd 7 get slow and not the one which I did overclock too much!?
i had similar problem with my nvidia p106-6g gpus on ethos. i have 2 similar rig same gpu mobo only difference memory amount. one of 4g other one 8g. one rig crashes with same config.
after that i applied a little different oc settings on crashed rig. apprx. %3 lower but before that you must be sure psu is enough.
what about memory? i guess 4gb is not enough for 8 gpu you should insert at least 8 or 16GB