The game is still very CPU dependent. Upgrading your i3-2125 to an i5 2500 or i5 3570 will make a difference in minimum frame rate. I dont think there is a system that can guarantee 50+FPS at max settings yet.
Few days ago i made a CPU upgrade from my old i3-2120 to i5-3570, and felt a huge fps increase. Also yesterday i accidently found a new AMD beta driver 13.2, so i installed this one aswell, and got a significant performance improvement.
So in fact, for example, if i had about ~40-60 fps while running in world, now i have 60 fps strictly (v-sync turned on). In lions arch i have ~35-60 fps.
Hope this reply helps someone to improve their feeling of game.
P.S. This game looks really pretty when playing at all max settings, it is worth to do everything that is possible to let yourself enjoy it.