try this -g 2 -I 13 --shaders 2048 -w256
use cgminer 2.11.4 do not set thread-concurrency let cgminer detect the best value for your cards, maybe try the last beta drivers 13.3, i get more than 720 kh/s with core1040/memory1750 with vcore unervolted and vmemory overvolted , i did order Arctic extreme cooler tried it on 1 card and it is amazing I am getting around 67 c°with these setting comparing to the other cards that are running @ 86 c° I did order more coolers for the other cards, it is worth every cent I did give.
This worked very well for me. I went from:
I 20
TC 24000
g 1
to
I 13
TC 10240
g 2
With the core clock staying at 1025, memory at 1800, and voltage at 1.063 each GPU went from 675 KH to 720 KH.