After 2-3 days experimenting, I can say that there are enough alternatives to Claymore's miner. With xmrig, xmr-stack and especially SRB I can achieve stable 450-500 h/s for tahiti 280 cards, 715-750 h/s for hawaii 390, and 910-930 for polaris 570 and 580 cards (with the usual bios mod and overclock as for ethereum). I don't need Claymore' s eth miner anymore also. Xmr is more profitable than eth, and with the coming reduction of the eth reward the minig of eth will be near its end. Thanks to Claymore for all his job so far, but it is time to move on!