x264/h264 audio synch problems at 1080p/24Hz

[stoked]

TV-Server Version: 1.0RC2 SVN20078
MediaPortal Version: 1.0RC2 SVN20078
MediaPortal Skin: Bluetwo Wide
Windows Version: XP SP3
CPU Type: Intel 2.4Ghz Core 2 Quad
HDD:
Memory: 4GB DDR2-800
Motherboard: Intel P5E-VM DO(TVserver), Giga-byte P35(TVclient1), Nvidia 8200(TVclient2)
Video Card: Onboard(TVserver), 8800GT(TVclient1), Onboard 8200(TVclient2)
Video Card Driver: 175.14
Sound Card: onboard
Sound Card AC3:
Sound Card Driver:
1. TV Card: Skystar2 DVB-S
1. TV Card Type: DVB-S
1. TV Card Driver: 4.4.3
2. TV Card: Twinhan 102G
2. TV Card Type: DVB-S
2. TV Card Driver:
3. TV Card:
3. TV Card Type:
3. TV Card Driver:
4. TV Card:
4. TV Card Type:
4. TV Card Driver:
MPEG2 Video Codec: Nvidia Video Decoder
MPEG2 Audio Codec: Nvidia Audio Decoder
h.264 Video Codec: Corecodec, ffdshow, Cyberlink PowerDVD8
HTPC Case: Origenae X11
Cooling:
Power Supply: Corsair 550W
Remote: Harmony 880, MCE Remote
TV: Sony 50" SXRD A3000, Optoma H71 Projector
TV - HTPC Connection: DVI, HDMI


I've been trying to debug this issue for quite some time on my Nvidia 8200 system. Basically if I watch x264/h264 videos at 24hz, the audio slow becomes unsynchronized, it usually plays faster than the video but is only noticeable after 20-30min of playback. However, this seems to only happen when I'm using CoreAVC or ffdshow. When I use Cyberlink PowerDVD8 codec the audio stays in sync, the problem is Cyberlink doesn't play quite a few of files properly. I can't seem to figure why Cyberlink works at 24hz and ffdshow/CoreAVC doesn't. I tested regular mpeg2 material at 24hz like DVD's and it works fine with no audio sync issues.