DSL Ideas and Suggestions :: DSL for PPC platform
You may want to try installing a basic Debian for PPC and see how slow it is if you don't mind installing to HDD for testing. Do you have your old Mac disks so you could roll back if necessary? or a spare HDD?
I'm just suggesting this as a real comparison between pure Debian PPC and Ubuntu PPC. Ubuntu is going to default to Gnome, but with Debian, you could get a CLI only PC and then apt-get Xwindows or Xorg and apt-get fluxbox, or apt-get fluxbox may just get you your base. I bet Gnome is as slow on an old PPC as it is on an old x86.
Someday I want to install Debian on my Sun Sparc I have in the garage.
original here.