Realtek HD microphone boost
Usually, mic boost is under the Record section of Volume control. If you have Realtek HD, however, these options are disabled.
You need to open up the Realtek Audio Manager and go to the Mixer tab. Then, under the Playback section, scroll to the right until you see Rear Pink In (or Front Pink In if you are using the front mic port). There is an Advanced Options button next to the Mute button. Click that and select Microphone Boost. How was this process considered intuitive?