Session exiting in GDM and XDM

["D. Nathan Hood" <nhood unlnotes01 unl edu>]

For a long time I was using XDM to control logins on my linux box, when
i downloaded and installed gnome i switched over to GDM, but quickly
noticed a problem.  every time i exit from x-windows under GDM, it does
a complete restart on the x-server (or something similar) while this is
not a major concern for the most part, my monitor doesn't agree 100%
with x-windows and i have to do some xvidtune tweaking to get the image
completely onto the screen.  when GDM restarts it completely restarts
the x-server so any changes i made in xvidtune are lost, and the screen
image is out of position again.  this doesn't happen under XDM.  for
some reason XDM doesn't do a complete restart of the x-server so when i
log out, the changes i made in xvidtune are kept by the system.

i like the looks of gdm alot more than i like xdm, is there any way i
can either make the xvidtune settings permanent (probably by editing
monitor settings someplace, but i don't know about that) or is there a
way to get GDM to behave more like XDM?

thanks in advance
-nathan hood