Guys I have MSI Armor RX 580 8GB.
Problem i have is Polaris bios mod utility shows that gpu has Hynix and Samsung memory, and both got only up to 2000 timings.
I tryed kinda standard timing for both memory, but so far i got stable 30 Mh -cclock 1300 -cvddc 970 -mclock 2160 (using around 98 W says HWInfo)
which is ok, just wonder if there is maybe better timings...
Does anyone have experience with those that could help me?
Also currently is it better to mine with windows or linux on those cards?!
Which OS you like more. If you have VEGA only Windows.
After modifying 1500-2000+ stripes on my Sapshire Nitro+ RX 580 8GB (Samsung) using PBE or SRBPolaris I try to verify with ATIflash and always get error on BIOS integrity:
AtiFlash.exe -v 0 bios_modified.rom
0x21/0x40000 bytes verified
ERROR: 0FL04Same error also when running -v on "Anoraks_Sapphire RX 580 Nitro(plus) 8GB Samsung Hynix_memshift-1750.rom"
What am I missing?

You need to do HEX mod, not possible with PBE or SRB to do this.
I don't understand, am I missing something here. I've successfully modded RX580's with PBE, this version
https://github.com/jaschaknack/PolarisBiosEditor, and have used the Anorak's BIOS's on the odd occasion, never needed to Hex edit an RX580 BIOS.
If you must Hex edit you can use this (I did it for a R9 270X)
https://anorak.tech/t/anoraks-amd-vbios-hex-modification-tutorial/126