I am big on only installing software that continues to get security updates if the machine is going to connect to the internet ... So I wouldn't recommend using a no longer supported version of XFree86. Here is what they say about the 3.3.x branch
QUOTE
XFree86 3.3.6 is no longer supported as of February 2002. There will neither be future updates nor fixes to this version, and bug reports and support questions related to this release will be ignored. This because despite our many attempts, the XFree86 Project could not fnd any interested in maintaining this branch, and so bowing to the inevitable, we have retired this series.
The oldest version of XFree86 that is supported is 4.3.x.
I use
x.org 6.8.1 on a Pentium II 233 laptop with 128mb of RAM and
XFCE4 as my Desktop Environment (it uses xfwm4 as the window manager).
I think it works as well as what I used to have installed on that laptop (which was a fluxbox windows manager and XFree86 4.3.x).