Of course, trying to squeeze the last juices from the cards, I actually gave them more than 2050 MHz, but I thought that if they work after a dozen or so hours, they are nothing
I will try to give them some more slack. Thank you for the suggestion.

I'm mining with 6x1080 and sometimes (rather irregularly) miner simply stops at any hour (looks like freezed), there is no error, GPUs are not loaded and I have to close the miner and fire again.
What could be the reason? How to solve it?