RESOLVED:
I fixed the problem by switching from cgminer 3.7.2 to 3.6.0. Also the slower card runs best with these settings and got a bit more out of other card using thread-concurrency 11200:
Card 2: 740kh/s
--thread-concurrency 8192 -g 2 --worksize 256 --gpu-engine 1082 --gpu-memclock 1500 --gpu-vddc 1.200 --gpu-fan 100 -I 13
Card 1: 770kh/s
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I have 2x ASUS 280x and I have tweaked them to find the best hash rate.
Card 1: 760kh/s
Card 2: 675kh/s - Since these cards are identical I have tried same settings, different settings/clocks, running them through different cgminer instances and different workers. It still won't hit 700+. Anyone have a similar issue?
ALSO: I noticed the (5s) average will jump every second or so 705kh to 645kh back and forth. The WU value is higher than the hash rate? In the other card it is about 9/10's like it should be.
--thread-concurrency 8192 -g 2 --worksize 256 --gpu-engine 1090 --gpu-memclock 1500 --gpu-vddc 1.150 --gpu-fan 80 -I 13
Neither card get HW errors or anything like that.
