Just a few more test I would like you to run try with aticonfig to set the memory clock lower at the same value that cause the app to have a -1 error. I don't have the at the aticonfig utility here but I believe it should be something like that
Code:
aticonfig --od-setclocks=0,1100
I suspect that your card might have a gpu bios with wrong values, as in it report min/max range that it won't accept as input value it will only accept value that it reports in its peak range. This would fit what the test result you have seen.