Comment 7 for bug 144182

Hm - and it works correct if you do the following:
1. on the login screen press Ctr-Alt-BackSpace - so the X-server starts again - then the colors are correct.
2. set the HorizSync and VertRefresh values manually in the xorg.conf:

Section "Monitor"
   Identifier "Generic Monitor"
   Option "DPMS"
   HorizSync 30-95
   VertRefresh 50-180
EndSection

I found it here:
http://ubuntuforums.org/archive/index.php/t-138110.html

It's just a bad workaround - maybe the vide driver hackers could implement the auto modeline search better?