Did you know what could be a problem?
Hi there. I don't know what the problem is as I'm having the same. Though I'm getting somewhere. Open after burner and detach your monitor. Make sure you can see all Gpu Power draw, and remove temperature so it doesn't take up as much space. Find your Gpu which looks unstable, then figure out which one it is. Now turn down your comp and simply switch it with another 1 on the PCI slot in your motherboard. Eg. Card nr 4 goes into slot nr 5,and vise versa.
This stabilized all my cards. And I haven't had a crash for 24 hours now.
Also, I stooped using any cards that's not Pascal.