I'm having that problem too. Unfortunately the boost doesn't seem to be a good solution because it is relative to the game sounds, so when the game sounds cut out, the microphone sound goes down in volume too.
To explain what I mean: I'm trying to record audio commentary on "World Of Tanks" game replays. By using the microphone boost at 9, I got my voice loud enough during the action part of the replay, when there are game sounds in the background. But when the replay ends and I want to add a few words at the end, when there are no game sounds, the mircrophone gets extremely quiet till you can hardly hear my voice anymore.