I have a HD 4350 graphics card and that smoothly plays Far Cry 3 at low settings and no overclocked. I usually OC the GPU from 600MHz to 650MHz and Memory Clock from 400MHz to 525MHz. This shows an increased memory bandwidth in GPU-Z. While overclocking the same, I see no difference in performance of the game. This is the issue with Far Cry 3 only.
Moreover, sometimes my drivers crashes frequently.
P.S: Using Windows 8 Enterprise.