Just downloaded and tried this driver. Odd thing is that (unless I'm still using the older 9.2) the new 9.3 driver seems to be no different! I don't see any speed increases in 3D nor in rendering (I'm trying KDE 4 here, and rendering - for example - with 'wobbly windows' with the 9.2 driver - was fine) .
Edit Video can still be problematic -- depends on the player. KDE 4's dragon player dies a lot x.x but playing with the command line version of mplayer (under slamd64 12.2), packages (.tgz) found here - http://www.amigib.nazwa.pl/linuks/slamd64_12.2/ (for mplayer and its deps) video seems to play ok and go to fullscreen and back without a crash by doing this:
Haven't tried it with anything but MPEG 2 videos so far (namely a brief test video I recorded from a freeview transport stream; that's digital TV, btw).
mplayer myvideo.mpg -vo gl