Hi, you probably need to update your nvidia drivers to the latest version. Hope this helps. Also, you don’t need to overclock the core clock speed since Eth is memory intensive. My settings for my rtx 3060ti is -500 core 2250 mem and 120 pl and the hashrate is 60.8Mh/s.
Today I had the same problem after massive overclocking. (get 66MHs@130W/-502/3500)
System crash, and after rebooting, and oc failed with two card from the five all the time. I solve te problem turn off the power, and changed PCIE slots.
I have the same temp problems from the beginnings. Once happend: one card fans not started after reboot, there was no temp data, and start overheating. wft?