It sounds like the problem here is that dpkg-reconfigure xserver-xorg is failing to generate correct information for the monitor section of the config file.
In each user's case, the h/v frequencies were either missing or set incorrectly. Xorg had difficulty determining a proper mode to use, and fell back to 640x480.
3zero2, I suspect your issue is completely unrelated, since you are able to achieve 1024x768 unlike the original bug reporter. Many others have reported that Ubuntu's Xorg settings max out at 1024x768, so I think your issue is simply a duplicate of that one. Thanks for offering to collect more info, but I think this one is already sufficiently well reported. Hopefully we'll figure out a fix soon.
It sounds like the problem here is that dpkg-reconfigure xserver-xorg is failing to generate correct information for the monitor section of the config file.
In each user's case, the h/v frequencies were either missing or set incorrectly. Xorg had difficulty determining a proper mode to use, and fell back to 640x480.
3zero2, I suspect your issue is completely unrelated, since you are able to achieve 1024x768 unlike the original bug reporter. Many others have reported that Ubuntu's Xorg settings max out at 1024x768, so I think your issue is simply a duplicate of that one. Thanks for offering to collect more info, but I think this one is already sufficiently well reported. Hopefully we'll figure out a fix soon.