Did test dagfix undervolting version on 2 different gpus - sapphire rx480 with original bios and sapphire rx580 with modded bios - no change at all in powerusage from socket. 2 gpus stay at same 370w and thats all (total system power consumtion). Did try everthing from 700 to 1100 and different power stages. Will continue to test on other graphic cards too but i am not optimistic about sapphires