Same problem here, static hum even with +0dB boost.
System spec:
Win 7 Ult 64bit
Asus Maximus VII Hero
Intel i7 4770K@3.9GHz
G.Skill Trident X DDR3 2400
Corsair CX500M PSU
Asus Strix GTX970
be quiet! Silent Base 800 window
5.1 Logitec speaker system
GE 1kW UPS
power bar with built-in surge protection
Tried with many MONO and STEREO electret microphones.
Tried with Windows and Realtek drivers.
Tried in rear and front port (even disconnecting the front cable from the mobo).
Tried separate input settings.
Tried on different sampling settings.
Now, I've tried to use stereo headphones as microphone, and the static hum
disappeared.
Maybe it has something to do with too high input impedance.
The only thing left to check is to swap the power supply. But I can't believe that Asus didn't make correct supply filtering.
Maybe will try to make external amplifier or put a cap and resistor. But due that the new mobos come with STEREO input (?) it might be useless...
http://www.hobby-hour.com/electronics/computer_microphone.phpASUS PLEASE MAKE ANY COMMENT!