Hurray Alex,

your possible fix from Comment 10 solve it halfway or maybe  fully even on my
slow Duron 1800, RV730 AGP (4650), if we separate the mosaic into a new bug
entry.

The SPEED is there, now.
I can play 2 H.264 VDPAU accelerated videos (854x480 and 1280x720)
simultaneously with ~35% idle rest on this little system.
Have a look at 2-times-mplayer-konsole.png attachment.

I've tested it with AGP and PCIE mode, both with same results.

The mosaic problem IS mouse cursor (hardware cursor?) related!
If the (big/fullscreen) video window coming up 'under' (over?) the mouse cursor
position I get immediately mosaic. When a smaller video window starts from
mouse cursor postion away UVD is excellent. Mosaic starts then not until mouse
cursor move over the video window. With mplayer this could be faster reached if
one seek into the video window.
See 2-times-mplayer-mosaic.png attachment.
Tested with AGP and PCIE mode.

Very nice!

-Dieter