[jb_daefo]

in one or both of the following two places someone has posted
a working xorg.conf that would help
the freebsd questions list
the forums at freebsd.org
Otherwise, the latter has long threads helping with xorg.
Cannot guess as to which would be quicker.
What I have done in the past is google for the specific chipset
"x800 OR R430" xorg.conf "xorg 7.4"
to obtain samples