OS X has many great design wins, but the mouse acceleration curve is not one of them. Using a mouse under OS X feels very unnatural if you’ve ever used another operating system. The pointer moves too slowly when you move the mouse a little and too quickly when you try to speed it up. This is because the default acceleration curve is S-shaped and far too steep.
Unfortunately, OS X (as of 10.5 Leopard anyway) provides no built-in mechanism to allow users to easily change the acceleration amount or even to turn it off. Luckily, there are some 3rd-party solutions that can correct the problem, though not all of them are free. Let’s take a look at 4 of them below.
