Questions About Coreavc

Need for Speed:

I need to optimize x264, VC-1, etc. playback. Forgive me if I'm missing the glaringly obvious, but I have been googling for over an hour and haven't found anything. Most of the guides I've found are more geared towards encoding. I'm looking for a conclusive source on how to configure my computer for the smoothest and least-CPU intensive playback of next-gen HD codecs (yes, even accepting small reductions in picture quality!). I'm using my 2GHz Pentium M laptop as an ad-hoc HTPC. With a DVI>HDMI cable, I can playback 720p x264-encoded (mkv enclosed) videos pretty well. 1080p seems to be right outside the limit of my CPU, though. 1080p WMV seems even worse. For the x264 mkvs, I'm using CoreAVC with Haali splitter in media player classic, and ffdshow audio. WMVs with ffdshow and MPC. I'm running Windows Server 2003 (would a Linux solution be better?) with non-essential services disabled, and I make sure to switch the display to the HDTV, not to clone it. I don't think hardw