Right now I have Gpu: Sapphire Amd Radeon 7770 ghz oc to 1075mhz gpu clock and 1250 mhz memory clock
Can i get better performance?
More aboutwhat radeon 7770
It depends on the card. But you probably can. Just keep going until it gets unstable, once it's unstable you can pull it back a little or up the voltage and keep going, just make sure it isn't getting to hot.
That is entirely up to your graphics card. No two cards will overclock exactly the same. If your card can remain stable and not over heat at a higher clock, then yes, you can get better performance. If not, then no.
I'm currently running mine (a basic Sapphire) at 1250 Core / 1300 memory. Another I played with would only hit 1130 core / 1275 memory.
Both identical cards.. So yes, there can be quite a bit of a difference.