Volume Step Adjuster allows you to adjust the increment/decrement step of your system volume when you use your multimedia keys. By default, this step is 2% or 4%, which may be not appropriate for high-precision setting. With Volume Step Adjuster you can set this volume step to any valid value, for example, you can set the volume step to 1% or even 0.1%. The real volume step resolution available depends on your device.
Note, however, that this tool only configures increment/decrement step. It does not adjusts increment/decrement speed or any other parameters.
This program will only run on Windows 7 and, probably, later versions. This app may work incorrectly or may not work at all, if you're running any programs which intercept volume control multimedia keys input.
Seems to do the job in Windows 8.1, but it disables the volume OSD, which is a deal-breaker. I need to visually see the volume level, particularly at low levels.
Works well also under Windows 8, interesting way of registering (hooking) hot keys and changing the system volume using an API. The usability is not very high for noobs, but i don't care ;)