[mythtv-users] What is a "dual core processor"?

Rod Smith mythtv at rodsbooks.com
Thu Dec 4 19:22:34 UTC 2008

On Thursday 04 December 2008 08:14:50 am ryan patterson wrote:
> You are lucky I have some first hand experience with the Pentium D on
> my experimental setup.  My Pentium D 3GHz can not play HD-PVR
> recordings smoothly through mythTV.  But it can play the same
> recordings smoothly through VLC (so it is "powerful enough" in
> theory).  The playback through mythTV is just barely not fast enough.
> Maybe if I changed to a more efficient X.org window manager and
> stopped every background process on the computer it would work?  I
> don't really care because I will use nvidia VDPAU for playback.

The window manager isn't likely to have an appreciable effect. What CAN have 
an effect is the X driver settings. As an example, I've got a 3GHz Celeron-D 
CPU that's always been just a little sluggish when playing HD content. The 
problem, examining top output, is that both mythfrontend and the X server 
consume about 50% of CPU time, so when one or the other spikes (as happens 
once every 2-30 seconds), there's a pause in playback. When this problem 
became serious for me (because I started wanting to watch more HD 
recordings), I investigated further, and discovered that I needed to set the 
following line in my /etc/X11/xorg.conf file's "Device" section:

    Option         "UseEvents" "True"

With this set, the X server began using about 10-20% CPU time and mythfrontend 
continued using 50% CPU time, with the result being smooth playback. This is, 
however, with an nVidia FX5200 graphics card and nVidia's proprietary 
drivers. This option may not be supported with all video cards, and there may 
be other tweaks necessary with other cards or drivers. My tale is 
illustrative of the fact that proper X configuration is required to get 
decent performance out of your hardware.

Rod Smith

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