iBook G4, No sound and poor video performance

Hi this is my first post,

Specs:
iBook G4 mid 2005
PowerPC G4 1.42 Ghz
1.5 GB DDRI SDRam
ATI Mobility Radeon 9550

First of all, I have no sound. I updated everything but nothing, also i searched on google but my problems werent fixed
I also have bad performance with my Radeon 9550, Do I have to install drivers?

greets