TMPGEnc produces choppy audio on Core 2 Duo system

[a2man]

I have used TMPGEnc 2.524 and earlier versions for several years with an Athlon XP 2500+ processor-based system without any problem to convert AVI to MPEG2 files and to edit MPEG2 files. Recently set up a new Core 2 Duo E6300-based system to begin to migrate to faster components, but both TMPGEnc 2.524 and the new 4.0 XPress version produce MPEG2 files with very choppy, stuttering audio using exactly the same file settings and source material that work fine on the older Athlon XP 2500+ system. Audio problem persists when files are played back on the older computer, so the problem is intrinsic to the encoding rather than the playback. I have not been able to find any mention of this issue. Is it known? Is there a fix?

[TBoneit]

Codecs? I would think they'd be different versions, if not maybe the audio codec has this problem and not the encoder itself.

[bigbs4]

Is it only choppy on the PC or does this carry over when burned to DVD?