Hi,
For now, rig is still stable for 22h and all 9 cards mining.
If its hold another 22h I started to thinking that the main issue is card/riser inside 16x slot... I had gen1 on all slots...
Gpu is 905 and mem 900. On the wall is about 1350W for whole system...
I removed the card from the x16 slot too. 2h stable now. Let's see if it holds.