I have peg II with g3, 512 mb & radeon 9200 se. I suppose that configuration is strong enough to run any gfx environment of any distribution (I had gentoo and it was pretty much quicker than suse). Its slowness can especially be seen when wallpaper is active.
Gentoo is fine tuned to your machine. SUSE uses the same binaries from embedded to IBM POWER servers. This makes software updates a lot more easy both for SUSE and for us users, but also has some performance drawbacks. The most striking difference is the lack of Altivec optimalization. It can not really be felt by server applications, but for multimedia applications sometimes significant. SUSE Linux PPC was originally targeted at IBM POWER servers...
How do I start 3d acceleration?
Open /etc/X11/xorg.conf in your favorite text editor
and add the following line to the modules section:
Restart your X server. 3D support will be enabled this time. It can't be set from YaST/sax2, as 3D is officially supported only for x86 binary ATI/Nvidia drivers.