I won't be getting the graphics card in a while so I want to make gaming performance right now as good as it can be. I have a H77 board, i5-3450 and a 650w power supply. Is there a way to overclock the graphics only?
No, just the turbo boost for cpu and choose performance vs quality.
Not even with third party oc programs, and for gaming the 2500 is really crap, the hd4000 already is, i cannot imagine how bad is the hd 2500.
Just buy a cheap gfx card like 7750 and it will perform 100 times better.