I'd try to reinstall the drivers, maybe something corrupted, also check temps, Downlaod MSI afterburner and see if you can control the fan speed, if you can't the regulaters the control the fans voltage could have burnt out from the power outage. I suggest getting a surge suppressor to keep that from happening again. It will say surge suppressor if it is, there are power bars that look like it, but are not.
It will keep a steady flow of power and less power spikes.