Having a really hard time finding proper settings. I thought I might have a bum card so I picked up a second 290x today, same results. Right now my best result is 850KH/s @ 885/1250 TC 32765 -g 1. I tried duplicating the settings in the OCN thread Ivan linked, but they don't work for me.
885mhz is super slow for the core...up that thing in the 1000-1100 territory and man up :p
I still prefer stock clock for my GPU although its not 290x, but I find it more energy efficient.