This tool gives you very fine-grained control over the speed of your pointer in Windows (versions XP thru Win11). The top slider has twice the resolution of the built-in mouse control panel in Windows. You can resize the app so only this slider is visible if you want a compact app to change just this one setting.

If you need even finer control the bottom two sliders slow the mouse down further. The new speed is a percentage of the speed set with the top slider. You can even set different speeds for left/right and up/down. This fine-grained adjustment requires that the app be running as administrator so that it can install a "mouse hook" which allows this low-level control. No mouse hook is used if you don't check the "enable" box.

Plus, you can change which direction is "up" for your mouse, so that you can hold it rotated to the left or right (or even upside down) if that's more ergonomic for you.

The newest feature is an option that allows you to filter out 1-pixel mouse movements (say if your mouse has the jitters).

This is fully functional and bug free, but has not been polished into a complete, commercial quality app with price to match. Primarily, it does not currently remember its settings when you quit, etc. If there is interest, I'll develop a paid, full featured version for $1 that will have these usability enhancements. Email me if that is something you'd buy so I know that's worth working on (link below)!