PC Tweaks Guide to Improve Graphics and Performance
Navigate to this folder:
<steaminstalldirectory>\steamapps\common\MARVEL VS. CAPCOM INFINITE\MVCI\Saved\Config\WindowsNoEditor
Scroll to the bottom, paste this in:
This will force Vsync off, which will eliminate the stuttering that occurs when you play the game in full screen mode. This will also reduce your input lag substantially.
To improve the visuals, add this directly below the r.Vsync=0 line:
This will remove the vaseline-smear style blur, giving you more crisp visuals.