sorry.....

both rigs:
core clock-1090
memory clock-1500
auto fan
no under voltage
and I don't use cgwatcher,so I can't help you with that.......
7970s are running @ 1090 core 1500 mem and you get 770KH/s? :-S
I am running a stock 7970 @ 1065 core 1800 mem and get 740KH/s and an Asus 7970 Direct CU II @ 1040 (higher clocks drop hash rate) and 1725 mem and get 714 KH/s :-S
You use the usual settings? -g 2, 8192, w 256, etc?
two rigs,5*7970 gigabyte,and 2*280x asus.......
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
sgminer -o stratum+tcp://eu.clevermining.com:3333 -u -p --kernel zuikkis --lookup-gap 2 -I 13 -g 2 -w 256 --thread-concurrency 8192 --gpu-powertune 20 --temp-overheat 85 --temp-cutoff 90 --expiry 1 --scan-time 1 --queue 0 --no-submit-stale
WU: around 90%.....
for me the best works kernel zuikkis.......
SGminer 4.1.....first rig windows 8.1 64x,second rig windows 7 32x......
and my 7970 are oc windforce 3x ,I don't know if that is important......
edit:can you guys please explain me how to insert image in post,thank you..... please don't tell me just to click on insert image,wont work....