So dont run intensity 17?
I run mine at 12, anything higher just throttles or crasches.
The thing is this rig *should* be able to run full intensity and get better hash rate, so I am doing what I can to achieve it, you know

anything over 17 intensity not working isnt normal.
Ok do this - its like mixing music - just set everything to zero and start again.
so you run a .Bat file obviously - set it to just start CGminer and only set intensity I 18
and tell me what happens - so copy your .bat and just run a vanilla one take out the screwing with the voltage and TH and Sharders - if it works , slowly bring things back until you find the problem.
** you can leve the SET group i.e GPU_MAX_ALLOC_PERCENT=100 etc.
thx digitalindustry, will try that and get back when I have results.