The settings above are for conservative background mining; if you want to crank it up, try phoenix with:

-k phatk2 VECTORS AGGRESSION=13 FASTLOOP=False WORKSIZE=256 PLATFORM=0 DEVICE=0

You must underclock the memory to 300MHz for the best performance, using a utility like MSI afterburner or Sapphire Trixx. If you use stock GPU RAM speeds, these settings will be better for you (but still not as good as the above with an underclock):

-k phatk2 VECTORS4 AGGRESSION=13 FASTLOOP=False WORKSIZE=64 PLATFORM=0 DEVICE=0