Scaling governor keeps getting set to 'ondemand' ?

So all videos in MythTV stutter? And you use XFCE? Probably gnome-power-manager is setting your cpu frequency scaling governor when the desktop logs in.

In gconf-editor under your mythtv account, go to /apps/gnome-power-manager/cpufreq, create a string-key named "policy_ac" give it "performance" as content. Any other ways will be overruled by this. Same thing for "policy_battery" if you happen to run mythfrontend on a laptop.

Gnome has a nice setting for this in their power manager preference.. if you enable that.. via gconf-editor.. haha.. :-/. Create a boolean named "cpufreq_show" in /apps/gnome-power-manager/cpufreq