If you are more into selecting some shapes using the mouse then it must be more important to you to lower the mouse speed so that you can select the shapes in a better way. Say, you are selecting some area while editing an image then if you do the same with normal speed mouse then chances are you may select some irregular shape.
Although in Windows you can slow down the speed of the mouse movement but this is not what I am conveying about in this post. While slowing the mouse using Windows slows down it completely but with the tool called SlowMousion, you can only slow down when selecting something.
SlowMousion is a small application that slows down mouse cursor’s speed when pressing and holding down a key or button. This allows you more sensitive mouse movements when drawing shapes, dragging something or anything you are doing with mouse.
You can also change the hotkey to be pressed when slowing the mouse motion. The tool is a nice way to put a brake on the mouse speed.