Hi,
I also have the same problem (Roccat Kave 5.1).
I'm on Win7 64bit SP1, i have the latest sound drivers and the latest BIOS. The sound is excellent and all five, but the mic is just too quiet.
My friends barely hear me talking, especially while we playing a game.
Purely to mention that i never had these problems with another brand motherboard.
FX-ROGerAMD FX-8350 @ 4.6 GHz ~ Corsair H100i ~ ASUS Crosshair V Formula-Z ~ Patriot Viper3 16GB @ 2400 MHz ~ ASUS HD7950 DC2T-V2 @ 1100/1500 ~ OCZ Vertex4 128GB ~ OCZ Vertex 4 128GB ~ Corsair AX 860 Platinum ~ Corsair Obsidian 650D ~ Dell U2311H