Asus M3N78-VM - Manual (Page 38)

1-26 Chapter 1: Product introduction
Playback of HD DVD and Blu-Ray Discs
The speed and bandwidth of the CPU/Memory, DVD player, and drivers
will affect the playback quality. Using the CPU/Memory of higher speed and
bandwidth with the higher-version DVD player and drivers will upgrade the
playback quality.
15. Optical S/PDIF Out port. This port connects an external audio output device
via an optical S/PDIF cable.
16. USB 2.0 ports 5 and 6. These two 4-pin Universal Serial Bus (USB) ports
are available for connecting USB 2.0 devices.