Thank you for the reply, i'll test it and give you feedback.

Btw. i tested mining with default settings (no mod bios/oc/undervolting/timing), PSU is Quality, MB has updated BIOS, i tried to change risers... Maybe it can be HW problem, motherboard is older ASUS P8H61-MX LX R0.2 or some riser is still shitty.

I understand there are many variants in the game;)