One of my SAPPHIRE NITRO RX580s is detected by the system and the miner, but fails to set DAG epoch on claymore. The system had been running fine for about a week then GPU4 had OpenCL hang and the system rebooted. Since then GPU4 refuses to start mining.
All other cards are working correctly with no problems at all.
Here is what I did to trouble shoot so far:
1) I swapped the connection to the motherboard with another GPU, and the problem follows the GPU having the issue
2) I reflashed the bios on the card which was successful, but still the card refuses to start mining
3) I made sure the USB cable was seated correctly/securely on both ends
4) I disabled the overclock/underclock on that specific card, still nothing
5) I replaced the riser, cable, and connector at the motherboard and still doesn't want to start mining
If anyone has any suggestions please let me know!