yea the best way is modded the bios to use less power and produce more speed that what's so nice about these cards now that use 14 NM chips . and they are just getting started ..
you can use afterburner or the WattTool but nothing works better so far then letting the card do it self but modding the bios and doing little tweaks with those tools .
Sorry if I ask a lot, but do you have a proper guide for RX 470 to undervolt (BIOS way)? I'd greatly appreciate that. Thanks!