Stock BIOS is best to use with 4XX cards here. Actually got better speeds when flashing back to stock from my ETH mod BIOS.
What hashrate do you get with stock bioses ?
My numbers with strap modded bioses.
470: 45-46 s/s
480: 49-50s/s
Same here, I'm getting 46~52 from strap modded BIOS at 1125/2150. RX480.