need help with hash rate dropped

I started mining raven for 3 wks with RTX 3060ti LHR. a day ago I restarted my pc and hash rate dropped from ~27.5 – 28.5 mh/s (before reset pc) to 11-12 mh/s for no reason. since the dropped I test it with different settings but can't get it back to 28 mh/s or at least 25 mh/s. tried everything I know to get hash back but can't. Does anyone know why?

window – T-rex – 2miners pool

oc before the drop: pw 90% mem 950 core 0 temp ~55 = ~27-28 mh/s

after the drop:

with same setting at first I got 11 mh/s – now is ~19 mh/s

same pw and mem but core +150-200 = ~20 mh/s