I managed to set my rig to steady 99,6MH and it stayed that way for 3 or 4 days and then all of a sudden, it became kind of unsteady... I OC with command line, and I always have to start the miner twice before there is any effect. Plus, the computer seems to restart here and there without any apparent reason... Where to investigate?

WIN10, claymore10, blockchain drivers, 3x rx570, 1x rx460.