Oh how do I love Redhat? Let me count the ways. redhat-config-xfree86 by default attempts to open a window on an X server. Great, except my monitor is reporting 'invalid input', so we have to do things the hard way. Manpage? nope. There's a --noui option that lets you set the various options (hsync, vsync or whatever) by hand, if you are clever enough to know the values.
Of course, if you have a working-enough X configuration to get a graphical display up, the UI program has a probe button. This reminds me of ISPs who's sole method of communication in case of trouble is via the 'net.