Need help overclocking an Xfx 7770 Double D

I have a fx 6300 CPU with 1600mhz patriot memory which I was easily able to overclock to 1866 and a XFx 7770 Double Dissapation fans which work really well. As of now Battlefield 3 is my most demanding game and I play battlefield with a mixture of ultra settings high and medium. The auto graphics give me decent graphics and really High frame rates 60-85 fps, however I would like to play with a little higher settings more comfortably. I tried overclocking but its been a total failure. All I am able to accomplish with both Msi afterburner or with the amd catalysist control center is overclocking the core 100mhz more; pushing it further or even touching the memory cause the display to fail. Its insane because I go to other forums and read of people maxing the card from 1ghz to 1.2ghz and the memory as well with stock fans. P.S. I haven't tinkered with the voltage oR anything. Any help would be fine and keep in mind I'm still very new to overclocking.

welll over volting maybe your next step if the card just stops. xfx should have their own overclocking utility. and alos to make sure your games run as fast as they can use the latest graphics driver which atm is 13.1