7970 gets about 550 at stock clocks. 6870 gets 260-280 and 5970 gets 640-680mh/s.
5000 series cards do extremely well with SDK 2.1, but since you have a 7970 in the mix you have to use SDK 2.6 which isnt so good.
I get 998mh/s from my setup (mild undervolt too) 430watts right now at the wall.
7970@975mhz
6550@650mhz
5870@885mhz
Any special flags you use for Diablo?
for CGminer I use these:
-v 2 -w 256 -g 4 -k phatk --gpu-memclock 300 --auto-fan --temp-target 69 -I 7
can I do the same for Diablo?