How to Change Your Mouse DPI in Windows 10

On the Devices page, click on “Mouse.” On the Mouse page, click on “Additional mouse options” under “Related settings.” In the “Mouse Properties” pop-up, click on “Pointer Options.” Use the slider under “Select a pointer speed” to adjust DPI.

Is 1200 DPI good for mouse?
A lower 400 DPI to 1000 DPI is best for FPS and other shooter games. You only need 400 DPI to 800 DPI for MOBA games. A 1000 DPI to 1200 DPI is the best setting for Real-Time strategy games

Is 3000 DPI too high?
Perfectly fine lowering the dpi and even recommended. Some mice may start getting more tracking errors, acceleration and input lag with high dpi. I think most people use 400-1600 in game.