sorry guys I need to know your miner
I use this
https://www.dropbox.com/sh/zhfbr8xh6zw0gi0/AACRBQNt63MeI18RlRXzgd-Ba/WIN-x11-sgminer-wolf-kernel-b2.zip?dl=0

my card  3x 290x oc
gpu 0: 63.oc     1514RPM | 7.032 M
gpu 1: 75.oc     2230RPM | 8.066 M
gpu 2: 75.oc     2230RPM | 8.066 M

total  23.13 Mhash


if you use another miner there is much difference between the gpu0 with gpu 1 and 2,
But the most touching Mhash are 18.23M

I tried everything, uninstall the drivers with DDU

changing position of video cards

without any positive results

MY PSU  corsair RM 850.

you have any solution?