Well with F62 if you set the engine at 1000 and memory at 1475, the voltage will drop to 1.2V - so will run significantly cooler and then the khs should be 700ish.
looks like i am running on a voltage locked card which has made things a bit tricky. Does anyone have success of flashing a Saphire BIOS onto a Gigabyte r797OC-3gd? Actually flashed it to the r9770TC-3gd the other night for that 1100/1500 default clock. Although everytime I go above a 1020/1040 gpu engine I go into a black screen crash so maybe I should flash back to the original 1000/1375 stock and go from there. At the moment I can run steady on a 925/1275 with TC8192 at 700 kh/s at 83 temp but would love to push it to 730-750 if possible
Or does anyone have any lower speed ratios that work for a 7970 preferable with a 8-900 GPU engine? you guys are awesome! thank you