Hi,
I just tried NIST5 GPU miner for the first time and even though I'm getting accepted shares they all got Diff 0.000/0.000 which seems a little odd to me.
Is this how it is supposed to work?
Also with my 280x I'm getting around 5.1 Mhash/s. Is this what I can expect from my GPU?
Use djm34's miner. You should get 12+ Mhash/s.
And remember update your AMD drivers to 14.6 beta.