Running FC2 on a PIII 733 with 192MB RAM should be no problem. I have a PIII 733 with 512MB and it is a faster machine than a 733 with winXP.
Make sure you don't have lots of unnecessary services running. Make sure that you are using UDMA access to your hard drives. hdparm will allow you to check that.
At a Konsole type
That will show you the manual page for hdparm. Or any other app that has a man page.
At Konsole type
That will show you what processes are running and how much resources they are using.
There is a great little system monitor named gkrellm that will allow you to monitor what your box is doing. FC2 runs well on a PIII 733. Don't get frustrated and quit. Dig around your system and see what is going on. It may take you a month or 2 to get acclimated to Linux. Sure works good once you start to learn how, where and why of it. I have FC2 with KDE running on a Celeron 400 with 196MB. It is not lightening but perfectly usable. It takes the Celeron 9 seconds to get firefox open on first instance. It takes the PIII 733 about 5 seconds.