I get 2.1m pps on my r9 290x on default settings. These seem optimum, as most settings don't seem to change anything. With sieve-size lowering it by about 600kpps if I go up or down.

It runs fine using -t 1 so I figured I could run the cpu miner as well but that caused the GPU to half in speed. Is there any way to run them both or is it a choice of 1 or the other?