Onboard sound stutters like mad

[jml]

Just completed a new built that went well until I encountered a strange problem with the RealTek AC’97 on-board sound. I want to send digital audio out via the coax S/PDIF interface from the mobo to my home theater pre/pro. When playing basic digital audio files (MP3s or Windows Media files) that are encoded at low bit rates, this works fine. I get two-channel stereo, as one would expect.

But when I play a DVD (from the DVD drive) or video (from either the boot drive or the storage volume) encoded with AC3/Dolby 5.1, the sound stutters like mad. The video plays fine, and my pre/pro recognizes the audio signal as Dolby 5.1. But the audio stutters like crazy. I’ve tried everything I know to do. I have installed newer drivers from the RealTek site. I have tried alternative nVidia sound drivers. I have removed all PCI cards just to make sure, all to no avail. :?

Any help or advice is appreciated.

Here’s my setup:

A8N-SLI Premium (Socket 939), BIOS Revision 1009
AMD Athlon 64 X2 3800+ Toledo
Gigabyte nVidia GeForce 7600GT SilentPipe II
Corsair Twinx 2048-3200c2 (2GB, dual channel)
1 Seagate Barracuda SATA 3Gbs 160GB Drive on nVidia SATA Controller as boot drive
4 Western Digital Caviar WD4000YR 400GB drives on Sil3114 Controller for storage (RAID 5)
NetGear WG311T Wireless Ethernet adapter
WinXP MCE 2005 Update Rollup 2

 

[Multiplectic]

- Which program are you using to watch your DVDs?
- Are you doing any overclocking? Try to return everything to stock.

 

[jml]

- Which program are you using to watch your DVDs?
- Are you doing any overclocking? Try to return everything to stock.

Using Video LAN Client, which is very reliable on many platforms.

And thanks for asking about OCing; forgot to mention that I'm not doing any OCing. The only manual setting I made was for memory timings, per the Corsair test/spec sheet. Using their recommended timings and voltage settings (2-3-3-6/2.75v).

I disabled as much as I could in BIOS, including the two wireline Ethernet controllers, QFan (using SpeedFan), etc.

 

[Multiplectic]

It seems like a codec problem... Try to install another AC3 codec, or try another program to watch your videos/movies/DVDs.
Try this page: http://www.free-codecs.com/
See if something solves your problem.
Good luck!