No, i meant that you 1st adjust and tweak the voltages the gpus need. A Bios change is the last step of a few - and not really needed.

It depends on: your miner (if there are options to adjust voltages/clocks), your OS (W10/Linux)

As Example on W10 you can use AMD Wattman (Part of the driver) to set profiles for every GPU and adjust there the clocks and voltages and you are set and no need to mod the Bios ...

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

my rom 260 sol/s in zcash, 28 mhz in ETH/ETC. If you need, pm email for me, i sent you my rom.

Drop Voltages and Clocks to save some juice :-)

875 1150
875 2050-2250 (depends on the Chips ya have ... and the mod ya have done ...)

Should get the 580 down to +- 85W GPU-Z