XvMC Video Output
If you have either an intel integrated graphics card or a NVidia 4, 5, 6, or 7 series card, you can enable XvMC video output. This takes a good portion of the load off of the CPU, and instead puts it on the graphics card. This can be a life saver for some users wanting to do HD playback with a lower end box, or even SD playback on a much lower end box.
* For Nvidia, you will have to modify /etc/X11/XvMCConfig to include this instead of its current contents
* For all cards, go to Utilities/Setup in the frontend. Choose Setup and then TV Settings and then Playback. Change the Preferred MPEG2 Decoder to be Standard XvMC. Restart your frontend app to ensure that /etc/X11/XvMCConfig is sourced and attempt to play back a file. You will notice the grey OSD rather then the normal color OSD.
For more information about XvMC, see the Official MythTV wiki. http://www.mythtv.org/wiki/index.php/XvMC