An update.. with an old release of HiveOs that embed Amd drivers 19.20 and lolminer i'm able to mine ethash4g at 23-25mh/s with 140W. Currently is 0,016ETC (1.4$) before electric bill. Not much but at this prices it's amazing an almost 9year gpu could be still make profits

Today a 7970 can mine 350Kh/s at 130W on VTC

At current difficulty 3x 7970 mine 1050/1100khs, more or less 4.5$/day before electric bill, so yes.. in this moment they are back to be profitable, not worth if you have to buy them but if you already have old cards sleeping they are worth a shoot until price of gpu and BTC will normalize