but mining cryptonight
1 of then ash at 750h\s and the other one 450\h\s
i tried to play a little bit the cc and mc but 450 is the best i could get
anyone could tell me what's wrong ??
Try to give those "lower Hashrate" card a dummy output. In most AMD card, dropping Hashrate is one of a regular issue.
Or may you need to test it first to disable one by one? Try the first card and disable the second card and so on. Just to make sure.