My friend Has Alien-ware 14x machine and it has a DMC board on it. Out of curiosity I want to know what the DMC board is meant for and what is its functionality.
This is a SiBeam WiHD/DMC controller card. It is used for streaming media to compatible WirelessHD devices. It broadcasts on a separate wireless frequency (60GHz), so it doesn't tie up your normal Wi-fi. It's also faster.
More info & some links:
Thread about the card on Notebookreview.com
More info from Dell Here.
WirelessHD on Wikipedia
WiHD Transmitter & Receiver kit on Amazon