[TRaSH]

do you got it all installed with HDMI like this way :
HTPC => AVR => TV
when you go to your audio settings in windows which audio formats does it say it supports ?
do you got is set up to exclusive mode and in XBMC to wasapi ?

[Mclarenmp4]

I had the same problem and it worked after disabling Dolby Digital (AC3) capable reciever in system/audio output. My TV doesn't support Dolby Digital and it was causing everything to run in slow motion, disabled that and it was fine.

[Dreamsword]

Thank you guys for all your responses.

Using Eden I got PCM sound on tv shows and on Movies Dolby or whatever the movie supports.

I have it plugged in that way HTPC => AVR => TV, but by doing it this I have no sound, it doesn't play via the speakers but it shows their is supposed to be sound.

I also tried it now with an Asus Xonar (HDMI to AVR and GFX to TV) and that works great. Still don't know why the other way don't work...