Need some advice

Hey there all. I'm still fairly new to mining and crypto. I am currently using RX 570's with Elpida memory to mine for RVN. If I leave settings alone my cards mine with no issue, but the wattage and temperature are higher than I would like. I have tried tuning the clocks and was able to get lower wattage, temps, and consistent hash rates, but after about 6 hours my hash rate would drop to 0 on one card until I would restart. I have been tinkering, but I can't seem to find a clock setting that keeps a card online or doesn't reject shares. I am currently using Minerstat OS. I have been trying to get my OC settings to 1150 core clock, 800 vdd, and 1750 mem clock. Anyone have suggestions? Thanks in advance.