One of my sticks from bitshopper is allways at cca. 10% HW errors. 8.5% was lowest I saw after 60mins and it stays arround 8.5-8.6%. I didn't tune anything but tried another way. Started at lowest clock @384, than @450... all the way up to 700, but allways is the same. VCORE=0.77V, VMEM=0.84V. I use Sipolar A-400 hub, only with this one stick in it for testing. Is it stick problem or should I try to tune it? Just need direction 'cause stock voltages looks ok, at least for clock speeds up to 600MHz...
Few sticks I have come across show this issue. Its rare, but the IO coms sometimes spit out garbage that is picked up as a hardware error, unfortunately no way to filter this out. As long as they hash fine you can ignore it (you just have to figure that 8.5% is 0% error for your stick when tuning).
I have found the - - benchmark setting to be very good at getting my HW below 1% for any clock speed