Built two new machines with dual Powercolor 270x cards -- neither mines well AT ALL.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814131532Both systems crash all the time with GUIMiner and produce tons of hardware errors with CGMiner (probably 99% HW errors)... trying replicate any .bat or .conf files from others with single cards does not work at all.
Any ideas ?
I have 10 other systems running dual cards... but 7950 and 7970 -- all no problem... but can't get these R9 270x cards under control at all.
Can you post a copy of the launch commands you're using? It sounds like your intensity is too high, or the memory, core clock is too high.