Are you using the front panel mic port or the back panel one?
My mic works fine if i connect it to the front panel or to the usb soundcard it came with, but if i connect to the rear mic port mine is also VERY quiet.
Case Corsair 600T || PSU CX Series™ Modular CX750M
Motherboard Maximus VI Hero || CPU Intel i5-4670K
Cooler Corsair H100 || Ram 16gb Corsair Vengence 1600 (4x4gb)
SSD 2 x Samsung 840 Evo (250gb) [RAID 0] (OS) || HHD WD 500gb Black
GPU EVGA 780ti SC ACX || OS Windows 8.1