Wow, I've never heard of this minecraft mod that would need a GTX 770...
a freind of me have gtx 660ti and just with shaders mod max settings (without ftb unleashed or a texture pack) he runs minecraft at 30-60 fps
i didn't mean that he have to get a gtx 770 i meant that a 770 would be more than enough
he could get a lower graphics card but i'm sure that 630 is not enough for what he wants to use it for (ftb and shader at max)