I run OS X Tiiger 10.4 on an iBook G3 800Mhz / 640Mb and it runs very well. Very decent OS. The only thing that suffers is flash/youtube.
Is flash for OS X inferior to the version shipped in 2002/3 for Windows XP then? As I never had a problem on that speed of Pentium 3 notebook surfing Youtube back in the past. I had a great G3 beige tower with the Wings A/V input output module I got for free, nice machine but boy is pre OS X Mac a pile of crap to look at AND use, worse than Workbench 3!
Personally if you can get OS X working nicely I would keep it with that, sorry can't help on how to find CPU speed or where the extra RAM slots in.
