[mythtv-users] Jerky TV, but mandrake mm-kernel cannot play live TV

[Sim]

I have a fairly successful mythtv setup now.  I still need to improve my 
remote control functionality, but it is pretty much there.

But I have one major issue, and that is the jerky live TV (and recordings) and 
of music.  I have a celeron 2.26Ghz with 256K RAM and a modern hard disk etc, 
and an XFX nvidia 5200 card, which should be enough.

I'm using Mandrake 10.2 as I know it better, and FC3 would not boot up with 
everything running properly so I could not switch to a remote control and I 
ended up loading modules each time.

With the stock 10.2 2.6.11 kernel KDETV and Amorak work fine but with mythtv I 
get an error message about:

Realtime priority would require SUID as root.
Changing from None to WatchingLiveTV
Video timing method: RTC

Needless to say I have SUID mythfrontend so the error message is misleading.

I've tried to use the 2.6.10-mm kernel but, although I then avoid the SUID 
message, live TV fails and I get errors about "remote encoders" now working.  
This is true with or without the nvidia drivers.

I've even tried recompiling the kernel on my own machine but still it blocks.

However, I did get it to play some MP3 and I think I could still hear the 
little jumps anyway.  I don't get these with other applications (although an 
earlier version of Amarok did give difficulties).

The picture jumping is sufficiently disturbing to damage the viewing 
experience, so I need to address it.  But I need some ideas to work on as i 
am stuck.  I'm using /dev/dsp for sound on a KDE machine - i'd love to use 
the ARTS support i've read about but not found.

Simon