DRI is hardware accelerated 3D rendering. You don't need it for music apps,
but you most probably need it for your Windows games, without direct
rendering you will use software rendering and get most likely get <5 fps in
OpenGL games. It may be nice to have direct rendering for xine too, since
xine can output its videos through OpenGL - don't know about MythTV though.

2006/9/23, Mark Knecht <markknecht@gmail.com>:
>
> On 9/22/06, Duncan <1i5t5.duncan@cox.net> wrote:
> > "Mark Knecht" <markknecht@gmail.com> posted
> > 5bdc1c8b0609221235i2270bbenf016d5fa7a1998ec@mail.gmail.com, excerpted
> > below, on  Fri, 22 Sep 2006 12:35:47 -0700:
> >
> > > It turns out that for me the problem was the ati-drivers package.
> > > Switching to the radeon driver today lowered the CPU usage back to the
> 9%
> > > range that I was used to:
> >
> > Thanks!  Always nice to see freedomware win. =8^)
> >
>
> I agree Duncan.
>
> Now, the one issue left for complete world domination would be to
> better understand how to get DRI working with this video adapter. Am I
> correct that DRI==3D? Or does DRI go further than just basic 3D and
> help other things like MythTV or something else I'm not thinking of at
> all?
>
> I do see these messages in xorg.0.log:
>
> (**) RADEON(0): RADEONSaveMode returns 0x709390
> (WW) RADEON(0): Enabling DRM support
>
>         *** Direct rendering support is highly experimental for Radeon
> 9500
>         *** and newer cards. The 3d mesa driver is not provided in this
> tree.
>         *** A very experimental (and incomplete) version is available
> from Mesa CVS.
>         *** Additional information can be found on
> http://r300.sourceforge.net
>         *** This message has been last modified on 2005-08-07.
>
> drmOpenDevice: node name is /dev/dri/card0
> drmOpenDevice: open result is 6, (OK)
>
> I do NOT do ANY Linux-based 3D stuff today. My workload is Mainly
> music applications - Ardour, etc., which do not care about 3D, web
> browsing, MythTV and Xine to watch movies.  Do I / should I care about
> DRI?
>
> I do occasionally play Windows games under Cedega. Would DRI ever help
> that sort of application?
>
> Anyway, things seem to be in pretty good shape. Maybe I should just
> leave good enough alone. ;-)
>
> Cheers,
> Mark
>
> P.S. - I'm still curious about trying your compiler flags but now
> there is no pressing timeframe to do it in on this machine. - MWK
> --
> gentoo-amd64@gentoo.org mailing list
>
>