My money's on HD DVD. Sony has a bad record with getting people to adopt new formats.blue-ray and hd-dvd.
yar, bios>>advanced>>onboard device configuration
Picture:
http://putstuff.putfile.com/48308/933363
Here you have 2 settings:
(1) HD Audio - set to: DISABLE
(2) FRONT PANEL support type - set this to: HD Audio
With the second setting configured like this you can connect X-Fi to the front panel connectors. I have a different X-Fi but your model is supposed to support HD audio connectors, I think. You can check this anyway.
Hope this helps 😉