Days when 7970/280x did 24-25MH are long gone, nowadays 1100/1500 gives you ~20-21MH. How are your temps?
True. Win 7 x 64. Genoil 1.0.5. My 7970 (
1000\1500 ) = 20.9 MH\s
I mine with the 7970, but with 830/1250. The hash rate is just 18.x. I tried to save the electricity.