Follow this steps on the first Link

https://www.reddit.com/r/FinalFantasy/comments/egxu9c/ff13_pc_unofficial_fixes/

Download the File from here

https://github.com/rebtd7/FF13Fix

Only Copy this two Files into the Directory the First link says to put them in :

d3d9.dll
&
FF13Fix

I Just tried it my self & the game is running much better, the funny thing is that i have a powerful Gaming PC & Graphics card but this game still stuttered before i applied the 2 Files but it doesn't anymore & i'm glad ^^

Hope it works for you as well

The stuttering is caused by the game's hotplugging feature. That is, the game is constantly looking for a controller in case you plugged one in while the game is running. The FF13 Fix linked above fixes this problem by removing the hotplugging feature, and it also removes the overly aggressive frame rate pacer, giving you better frame rate. Alternatively, the game will stop searching a controller if you plug one in, but you may still want to install the FF13 Fix, as it optimizes the game's performance and fixes the Libra text bug, among other things.

Originally posted by Serafie1999AD:

The stuttering is caused by the game's hotplugging feature. That is, the game is constantly looking for a controller in case you plugged one in while the game is running. The FF13 Fix linked above fixes this problem by removing the hotplugging feature, and it also removes the overly aggressive frame rate pacer, giving you better frame rate. Alternatively, the game will stop searching a controller if you plug one in, but you may still want to install the FF13 Fix, as it optimizes the game's performance and fixes the Libra text bug, among other things.

Wait all I have to do is plug in a controller? Also how the hell did they miss this simple bug? I get raked over the coals if I miss a bug like this with my coding work!!!

Also within FF13fix.ini change IngameFrameRateLimit = 0 to IngameFrameRateLimit = -1
also PresentationInterval = 0 to PresentationInterval = 1 and TripleBuffering = -1 to TripleBuffering = 1 run game Fullscreen. Zero stutter, for me. Same with FFXIII-2.

Plugging in a controller solved it for me. Thank you.

Easy Fix is to emulate the controller, if you have no controller to plug-in...
Simply install "vJoy" - worked like a charm for me!