Did you ever make a ROM for your cards, and are they P/N 113-1E366CU-S5S ?
All the roms I find are for P/N 113-BE366EU-Z48
I just picked up 5 x Sapphire Nitro+ SE (Micron Memory)
All 5 of them hash at 29.6-30.5mhs in silent mode without touching the bios. Running Aug 23 blockchain driver.
My oc settings are:
Core: 1150
Memory: 2250
Core Undervolt: -96
Memory Undervolt: -96
Fans: 50-80%
All above is applied via command line to Claymore 10.2
This gives a power at the wall of 125w per card and 83w in GPUz
The cards have been running for 12hrs with no errors at all and temps between 50-60C
The only odd thing i find is that in Polaris it only has 1 set of straps 0: which is why i havnt bios modded them.
ETH: 0x66ff2c45e37f0d574016c28651866ac07ddf27a5