This mitigates the constant small hitches and stutters of the game to a certain extent. It doesn't get rid of them entirely and does change the fact that Far Cry 3 simply runs bad on anything over 60 FPS.

Simply use Task Manager and set the core affinity to 4 CPU cores for the running Far Cry 3 executable. You'll have to do this every time you play the game.

If you want a more permanent solution you can use Process Lasso to achieve the same thing but without the need to re-apply this every time you launch the game.

This helped me and a friend of mine with the crippling freezes we experienced with the game as of lately. It's a permanent solution and only needs to be applied once.

Search for "Exploit Protection" in the Windows search bar. Click on it and a window will pop up.

In that window go to "Program settings" and add a program by clicking on the plus sign at the top.

An explorer window will pop up.

Navigate to the game folder of Far Cry 3. Head into the "bin" folder and you will find all executable files of the game. Pick an executable file and a smaller window should pop up.

In that window scroll down until you find a setting called "Control Flow Guard" (CFG).

Tick the box to override the system settings and now click on the toggle to disable CFG. Click on apply and you are done. Repeat this step with all 4 executable files related to Far Cry 3.

This might depend entirely on your specific hardware but for me Borderless Window Mode and Windowed Mode cut my frame rate in half and result in a very choppy game. Using Fullscreen Mode works entirely fine. The game still has some weird issues with Alt-Tabbing and also often suffers from morphed UI elements.