XBOX 360 5.1 dolby digital lag

[riku]

I have connected the optical out of the xbox 360 to the I/O drive of my X-Fi fatality sound card, and I notice a lag when using 5.1, not when using stereo. Why is this? The sound is heard a bit later than when it should, which is made even more abvious if connecting the ordinary RCA stereo jacks as well, then the delay is obvious, as the analog stereo is heard first, and that works fine.
Changing the optical wire makes no difference.

[Jei]

Have you tried updating the sound card drivers?

I'm running a 5metre optical cable from the 360 to my sony amp and there's no lag whatsoever.

[riku]

yes drivers all up to date.

[riku]

how much did that sony amp cost you?could I connect it to my existing 7 speaker setup?

[Jei]

It's a Sony DAV-S550 that i'm using as an Amp. The dvd laser went down last yr but it does the job, DTS, DD5.1 etc.

[marcus]

oops delete me plz