Dark Souls 2 is flawless regarding the optimization. The game works perfect even on older PCs.
To tweak the graphics
Go to “Video” > choose “Full Screen”, the default resolution for your monitor, Auto-detect best rendering settings: “on”.
From the second tab, set “Change all settings” to high, and start the game.
If it runs flawless, leave the settings as they are and enjoy the game.
If not, the first options that you want to turn off are “Antialiasing”, “Anisotropic Filtering” to medium, and SSAO to off.
On my system (Intel I3 3GHz, 8 gigabytes RAM, ATI Radeon HD 5670 (1 GB RAM), the game runs perfect, no framerate drop or any other issues.
To enhance the graphics, expect in the next days/weeks, some mods, created by the fans. Such mods will improve the textures and the overall look of the game.