As I was updating my mining scripts and profitability calculations I stumbled on UTC and ended up with the same problem I was having with CACH, fortunately they're either more helpful in that thread, or they've been on a higher n factor for longer, so settings were easy to get from there, and made a WORLD of difference when I tried the same settings for CACH mining -
R9 280x -
-I 12 -w 256 -g 2 --thread-concurrency 16384
Got me up to about 136 kh/s per 280x from the 75 or 80 or so I was getting when I was fumbling around with settings myself.
Yea, one of my rigs has 2 cards, one of them is runing with 15kh/s oO and the other one with 140kh/s. Any idea whats up?