so here is my red devil 8GB ROM (sorry not 4GB) for the RX480
I'm calling it v2 because its basically the exact same settings as my V2 rom for the ref 480
You should get 31MH ETH and 340MH SC with this and around 170w at the wall with a gold PSU @ 230v
Temps are silly good as this card has a fantastic cooler and heat sink system and runs around 40% rpm at 71-73c in a hot room and is very quite
mine shows 57w GPU power but I don't believe that for a sec and expect there is a bug some where either in the card or GPUz and I declare this data as rubbish.
this card has been rock solid with these settings and I'm very pleased with it.
enjoy and flash at your own risk.
this is using the 1750 strap in the 2000 strap. I haven't had time to poke around with other straps but will look at that over the coming week as I expect there is a good option for 29MH low power like the ref card
ps: don't forget to reset after rebooting from the flashing and lower the mem to 950, you also have the option of more mem if you feel yours can take it mine are happy up to 2250 but show mem errors in HWINFO so dropped um down for the reliability and less power