I have a rx 5700 xt MSI Mech on Windows 10.  

I run it with rx580s. It works fine at 57mh/s but will randomly cut back to 47mh/s(sometimes after 2 days, sometimes after 2 hours. I tried lowering the clock/mem even down to 52mh/s but this still happens randomly and I have to reboot in order to fix it.

Any ideas whats wrong or how to diagnose it?

Thanks