Far Cry 3
Post FX has the most impact on performance and the least impact on visual representation. I strongly recommend either setting it on low or completely removing it. Removing Post FX significantly decreases stuttering and increases performance. In order to remove Post FX completely, you must navigate to your GamerProfile.xml which is located in USER/DOCUMENTS/MYGAMES/FARCRY3. Once you are there open the xml file and find PostFxQuality, set it to false in order to completely disable Post FX. It should look like this PostFxQuality="false".Vertical Synchronization
Like you may already know there are two different V-Sync options. Option 1 enables it and caps the frame rate at 60 FPS. Option 2 does the same except it locks the FPS at 30. First and foremost I strongly recommend using V-Sync as it gives additional smoothness to the game and removes a portion of stuttering. The option which you should use depends on what FPS you would like to run the game on. If you want to run the game at 120 FPS then I suggest disabling the in-game V-Sync and enable adaptive V-Sync either in your drivers command center or using a third-party-software like RivaTuner, Dxtory etc. Be advised that if you cant maintain a frame rate ranging from 31 to 60 while using V-Sync option 1 then the game will cap your framerate at 30 fps while still using V-Sync. If you had a major drop in frames and V-Sync capped you at 30 FPS then you should ALT + ENTER the game and then RE-ALT+ENTER the game again in order for the cap to increase to 60 fps again.Triple Buffering
People who experience heavy stuttering are advised to use Triple Buffering which can be enabled using third-party-software, personally I would recommend using RivaTuner. Triple Buffering decreases stuttering and gives additional smoothness to the game.GPU Max Buffered Frames
Do experiment with different GPU max buffered frames settings and use the one which fits you the most. I have set it to 2 as it gives me the highest frame rate in the game. From my experience lower amounts have the highest efficiency. Higher amounts impact performance but only in a slight way. Setting the right amount of GPU Max Buffered Frames will give you a boost in frames ranging from 1 to 5. Not a drastic improvement but worth trying out.Ambient Occlusion
There are three different ambient occlusion settings available in the game. Namely, SSAO, HDAO and HBAO. Nvidia GPU users should use Horizontal-Based-Ambient-Occlusion. AMD GPU users should use High-Definition-Ambient-Occlusion. Screen-Space-Ambient-Occlusion is the "worst" looking AO option and should be used by people with not so capable hardware. People with weak hardware Should use DirectX9 which completely disables AO.RAM Frequency (Speed)
Higher RAM frequency is recommended. Be sure to run you RAM at its highest capable speed. I have 2133MHz RAM but accidently ran it at 1600MHz, when I set my RAM frequency to 2133MHz the stuttering in the game decreased and random FPS drops were eliminated therefore providing a significantly better experience in-game. Make sure you are running your RAM at its highest speed. However DO NOT overclock your RAM as it will cause instabilities.Graphical Settings
If you would like to gain performance by decreasing graphical settings then you should consider decreasing Shadows and Ambient Lighting as those are the most demanding options which have the most effect and impact on performance. You can also consider decreasing other options but those do not have as drastic impacts on performance.Multithreaded Rendering
This option cannot be found in the graphics menu or anywhere else in the game. It can only be found in the GamerProfile.xml, the one we change in order to remove Post FX. Multithreaed Rendering uses more processor threads to render. Initially it is set to 0 meaning it is disabled and inactive. You can enable it by setting it to 1. It should look like this D3D11MultithreadedRendering="0". Please be advised that it only functions if you use DirectX 11. After enabling it you either gain performance or lose it. If you lost performance and would like to revert back do not set it back to 0 as it wont work that way. You will have to completely delete the GamerProfile.xml file. Dont worry, it will appear again after you launch the game. Personally I have Multithreaded rendering disabled even though I have an i7 4930K, for some reason I lose a noticeable amount of performance and gain additional stuttering. Therefore I have it disabled. Some said that they have benefited from enabling the option.Make sure that after you have edited the GamerProfile.xml, you set the file to Read-Only in the properties menu. This is very important as otherwise you wont notice any changes due to the fact that the changes that you have made do not come into effect.
Also be sure to check out my guide on how to completely remove the HUD from the game. The link is in my signature.
I run the game Maxed Out at 2560x1440. I have Post FX and AA disabled. The game runs at a constant 60 fps with V-Sync enabled. I use HDAO and have set Max GPU Buffered Frames to 2. Alpha to Coverage is set to enhanced.