Might be too much OC.
Try another miner like T-Rex.
If you get same rejects lower oc.
1.62kh/watt seems a bit too high for me.
I am under 1.6kh/w, even on 2080 rigs.
...
Yes, my bad. Was playing with OC and in some moment the miner didn't liked it. So it was registering bad shares even after resetting OC. I reopened the miner again and its stable now for 11 hours.
https://i.ibb.co/m0gK4JN/zenemy-ok.jpgI was adjusting power limit last night, and i got 10W @ 1.5MH/s @ 3°C less.
Speaking about kH/W, I don't know if this is the software bad reading or my psu. But i can see strange spikes all over the place in miner software:
P:132-135W, E: 154-166kH/W
Like this one P:117W, 181.74kH/W
https://i.ibb.co/FxVdZM3/consumption.jpg//offtopicFor now I'm just looking how all this thing works, using one RTX 2070s. I have "free" electricity, it comes included in my apartment fix rent bill. So I guess, 2-3 GPU rig, without sounding the alarms should be good.