http://www.nvidia.com/object/dvd_de...-223-trial.html

Release Notes

Support for High Definition (HD) inverse telecine on compatible GPUs. See http://www.nvidia.com/page/purevideo.html for a list of supported GPUs.
After installing the PureVideo Decoder and using the MCE "speaker setup" wizard to select 5.1 speakers, the audio will only be set in 2 channel stereo mode. This is a known issue with Microsoft Media Center Edition 2005 Update Rollup2. You may download this patch to fix the problem. The patch sets the proper value for 5.1 analog and must be run after using the speaker setup wizard. Note: You must run this patch every time after you run the wizard in order for the settings to remain active.
Other compatibility fixes, click here to view the User's Guide