anormal playback rate behavior

[mhanor]

well... I'm a complete fool
I don't know why I remember that DivX video files were playing ok, but they don't, at least not all of them.

divx+mp3 -> playing ok (at least some of them)
xvid+mp3 -> not ok
divx+ac3 -> not ok
xvid+ac3 -> not ok
divx+other audio codec (don't know what codec, BSPlayer & Media Player Classic don't list it in the filters list) -> ok
xvid+the same "other audio codec" -> ok

where divx is DivX 5.2.1, xvid is XviD 1.1.0 beta 2, mp3 is MPEG Layer-3 Decoder 1.9 (build 311) and ac3 is AC3Filter 0.70b.

Here comes the fun part: after disabling the sound card, all files played correctly at custom playback rates.
Selecting "Basic acceleration" for Audio Playback, in Sound and Multimedia (or in DirectX Diagnostic Tool - same thing) resulted in correct playback at custom rates, with the sound enabled, no matter the codecs used.

My sound card is a standard sound card based on CMedia CMI8738 6ch, using the latest drivers available on windowsupdate.microsoft.com (if I remember correctly)

thanks for the help, guys...

I'm still interested in knowing what controls the normal and custom playback rate. The audio driver could trigger such a behavior? Especially the system reset... without a BSOD