Playback help

[Smokin Cola]

Apologies if someone has already posted something similar to this, as I'm sure they have but.......

My Current system spec is

Cpu: Intel Core 2 Duo E6600 @ 2.4Ghz
Memory: 2GB DDR2
Gpu: Radeon X1950XTX (512MB GDDR4 @ stock speed)
Motherboard: Intel 975X Chipset (Asus P5W-DH)
Sound card: Soundblaster X-Fi Fatal1y Edition
Monitor: Hyundai W240D ( 24" PVA version @ 1920 x 1200 via DVI)
Blu-Ray Drive: Pioneer BDR-202BK

Playback software: Cyberlink Power DVD Ultra (patched to v7.3)

The problem is this... my playback is juddery as heck, sound sync is off, and video playback is jerky. Can't figure out why. My cpu alone should be enough to decode the video without even needing the graphics card. I'm guessing the cyberlink software is the weak link but I can't find a remedy for it. I've updated my graphics card drivers to the latest ones available (currently Catalyst 8.3) and then updated my sound card drivers (using Beta drivers from Creative's site, the last offical update was 2006 or something !). I did originally try with the software that came with my blu-ray drive that was 'Cyberlink BD Solution Suite' featuring a cut down version of Power DVD 7.1 that required patching to version 7.3 for playback of Blu-Ray (which I did). I assumed that the reason playback was bad was because of a conflict with my sound card, cut down version of power DVD has limited sound support compared to the 'Ultra' version (as I'm sure you all know), but if anything the Ultra version is worse.

Anyone got any ideas ? Short of 'buy a PS3' or 'buy a standalone Blu-Ray player'.

Also downloaded Cyberlink's 'BD Advisor' and it 'green lights' everything in my system for playback

Cheers in advance for any advice