yeah 960 core here as well. Mem takes 1350 and then some I just stopped at 1350.
With the AMD overclocking tool found here I did get 1000 core it wasn't really that stable.
It really depended on the game, Crysis warhead yes ....War hammer rise of caos not at allhttp://www.techpowerup.com/downloads/1128/AMD_GPU_Clock_Tool_v0.9.8.html
regardless use the vista version it works.
Then again maybe just do what moto said.