Originally Posted by Intel (website)
Direct Media Interface
To meet the device-to-memory bandwidth requirements of PCIe, SATA, USB 2.0, Intel HD Audio and others, a proprietary serial interface, based on PCIe, was developed, the DMI link. This link connects the ICH6-M and the GMCH. It offers 2 GB/s maximum bandwidth compared to 266 MB/savailable with the ICH4-M hub interface. The DMI integrates priority-based servicing to allow concurrent traffic and isochronous data transfer capabilities for Intel HD Audio.