Drivers are 16.12.1, using per profile overclock for the miner, with 1050/1500 clocks (stock voltage) and manual fan control at 2000rpm. Speeds are 840H/s for 82*C.
Config is: no CPU use at all, 800 raw intensity, 2 threads, worksize 16.
I do not think its possible to run it any faster without touching voltages and increasing clocks (and power consumption).
According to GPU-Z, average Power In is 120-130W. With the rest of the system on idle and 85% power efficiency, this comes to maybe around 250W from the wall.
Does this looks good?
I believe 290x alone's peak power is > 300 watts. You should ask this in the xmr mining thread.