Damn, my 290x (Hynix) keeps crashing (on stock settings) after few hours of mining. Program freezes so bad that I need to restart computer. I got 2 rigs each has 5 gpus (280x, 290x) and I only got problem with 1 card. I tryed the card which crashed on both rigs and I get same results. It works good on claymores monero miner. Is there anything I can do? Any ideas? I had this problem on all versions.
Have you tried lowering eth mining intensity with '-ethi'? Default is 8, so use -ethi 8,8,8,8,7 with 7 where the bad GPU is, then try 6..5..4 etc until it stops crashing. Are you dual mining? if so try lowering intensity of whatever else you're mining.