Far Cry 3 vsync and frame buffering.

[zarx]

just experiment and find out what works best for you on your system.
If you are using Vsync, max buffered frames should be set to 2 or 3, 3 should make performance smoother but it may cause a tiny bit of extra latency, aka the time it takes the game to show the result of your input but most people won't notice the difference as long as you have a decent framerate.