Anyone that has used a laptop with a touchpad and external mouse knows using the same pointer speed (“sensitivity”) for both is not ideal. Unfortunately, Windows does not allow users to customize different speeds for touchpads and external mice. That is why AutoSensitivity was created.
What Is It
AutoSensitivity is an open source program that allows you to set different pointer speeds/sensitivities for touchpad and external mouse. When it detects you are using an external mouse, it automatically changes the pointer speed setting in Windows (the one found in Control Panel -> Mouse -> Pointer Options -> Motion) to the Mouse level you set in AutoSensitivity. When it detects you are not using an external mouse (in other words, using the touchpad), it automatically changes the pointer speed setting in Windows to the Touchpad level you set in AutoSensitivity.
After you install AutoSensitivity, run it and set the pointer speed levels you desire for touchpad and mouse by moving the sliders for reach respective setting. Then simply hit the Minimize button. AutoSensitivity sits in your system tray and automatically makes adjustments to the pointer speed setting in Windows as you connect or disconnect an external mouse.
The Get Current button allows you to get the level currently set for the pointer speed; and the Apply button allows you to instantly apply that new sensitivity to the pointer speed setting in Windows.
Since AutoSensitivity is a program you (probably) want running all the time, it has the ability to autorun at Windows boot; and the ability to automatically start minimized, so you don’t have to see it until you need to change a setting.
“What If I Use Touchpad And Mouse At The Same time?”
If you use a touchpad and external mouse at the same time (i.e. you have external mouse connected but have not disabled the touchpad), then the sensitivity setting you set for Mouse in AutoSensitivity is what will be applied for both. Unfortunately it just isn’t possible to have different pointer speeds for touchpad and external mouse concurrently without custom drivers — that is a limitation of Windows.
AutoSensitivity would be a lot more useful if it was portable seeing as many people that who would want to use it are probably those people that use laptops for work and travel (you know, the laptops that may not allow installation of unapproved software). However, even its current form, AutoSensitivity is very useful for those of us annoyed by having to use the same sensitivity for touchpad and mouse.
You can grab AutoSensitivity from the links below:
Version reviewed: v1.4
Supported OS: Windows XP/Vista/Win7
.NET Framework 3.5 is required
Download size: 2 KB
Malware status: VirusTotal malware scan (0/43) 
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