First your hardware configuration should be more than enough to give you stutter free 1080i. I have the same card as you and have stutter free HDTV 1080i.
I can suggest you to:
- Try different codecs. In my configuration I'm not able to use cyberlink, they give me heavy stutter. I use microsoft codec included in windows 7 (unfortunately you're under vista). From (I think) RC2 and up I have this behaviour (before I used cyberlink powerdvd9 codecs without problems)
- Update all drivers and bios to latest versions. Also the one of the chipset and audio.
- Try to disable aero features (like transparency) that can bring load on your GPU. Leave aero itself enabled.
- Try to disable unused services on vista. vista is much more heavy than windows 7. There are guides out there on how to do this.
Last resort could be an upgrade to windows 7. I think is an OS that is much more reliable for real time services than vista.
Try different codecs? The one I'm using is my gold standard...
I'm using latest catalyst, bios, and audio. I never installed any chipset drivers, so I'm MS only there.
Disable aero bits to play hd video??
Upgrade to windows 7???
Thanks for the suggestions, but I reckon the problem most likely lies with MP1.1... Any suggestions in that direction?