Ah shit brand new, damnnn that would raise the $ per hash cost to an uneconomical standpoint for our second rig. (as the payback would be less).

Ummm I dunno on rx480 would probably insult you on the price as you got brand new but about $180.

580 i got no idea of.

Im looking to rig up with used Radeon HD 7870, Radeon R9 HD 7990 and Radeon R9 295X2.

Best of luck solving your problem though bro, and your GPUS are resaleable anyways.