I'm at 1180/1350 @ 1.165v completely OCCT GPU stable for 8 hours, which is unrealistic, but I like to run my rigs 24/7 Stable. Runs all benchmarks and gaming, and 24/7 stable. the difference between 1180/1350 and 1220/1450 is not noticable gaming, so not worth it to me. Down the road I may pump more juice, but it won't be needed for a while since I am setting up crossfire in the next day or two.
I can go as high as 1220/1450 stable @ 1.165v for Gaming stable, but find OCCT GPU Load usually will freeze things up within a few hours.