On your mouse settings you may have noticed the option called Ripple Control. The purpose of this option is to make your mouse cursor movement appear smooth at high DPI.
However, this is done by recalculating the mouse input, and therefore it will create some delays, similar to MotionSync. For that reason, we do not recommend using it for games that require reactivity such as FPS games.
The Ripple control is only effective at high DPI settings. You will notice that at high DPI settings, mouse tracking curves are less smooth.
Turning Ripple Control on will make tracking look more smooth at higher DPI, you can easily test this using MS Paint and changing settings just like on the pictures shown on this FAQ.