a 23inch display is going to beat the crap out of a 32mb 9200 chip.
these things dont have much graphics woomph.

you need to try something more normal like 800x600

4200rpm laptop drives arent great either.
they have crappy latency, and they stop and take a break every 30secs.
there might also be sleep settings that need to be changed.
also running content from the same drive as the os drive causes dreadful problems even on a g5

and you might need quite a bit of memory between 512mb and 1gb to keep down virtual memory cacheing,