On one of our 2 servers on boot the console screen is normal and legible up until the point gdm loads. That loads fine and the display is OK. However the boot console Alt-F1 and the log console Alt-F10 and all of the other text mode screens are then out of sync and seem to be trying to display in a mode the screen can't handle.
This server has a graphics card which cannot take the full 1920x1080 the monitor is capable of. That is one of the differences beteen the servers. They share the monitor via a KVM.
So the question is why does the screen resolution/refresh rate for consoles get changed when gdm starts and where do i go to configure this? I have found a lot about the console not being legible on first boot but not about this situation. Changing the properties of the GDM display does not seem to have any effect.