Ah 480's in which case a good ol' BIOS mod should get them into the 28-30 territory. I've currently got 7 RX (4/580's) sitting at 210mh/s reported. I don't know how EthOS handles things since I'm on windows ten, but from the impression I get Linux appears to be the more flexible in terms of cards/mods than windows. I can give you some guidance in terms of the flashing process if you need it in terms of software and process (though if you go through my limited know-how you'll be flashing in windows).