I've had a scour of the forum and I cannot see anything immediately which would assist. Does anyone have any guidance, or some quick settings, to get a mild overclock without inducing tearing, artefacts or voltage changes?
Powerlimit to +20%
gpu clock to 1100 or 1150
mem clock to 1500
probably it will run with default voltages.
The only thing that will cause tearing is disabling vsync.
As above, push the power up to the maximum, then increase the clock until it's no longer stable. Don't increase the memory clock until you've got a stable core overclock (the 7970 has a ton of memory bandwidth). 1100/1500 should be easy unless your stock voltage is unusually low.