I've got an old Mitsubishi Diamond Scan 20 monitor that I put on my experimental arch box; I had this set up for another old monitor that was smaller and it worked fine.
Now when I boot, immediately after the grub screen, I get some screen roll (up and down the screen, seems to be moving up), white horizontal lines that flicker all over the screen, then it settles down and shows me the latter portion of the boot messages and gets to a login prompt. From that point I"m ok, unless I go into X (I'm running KDE). X also runs fine, but when I leave I get the rolling screen again, but this time it doesn't stop rolling. If I go back into X, it's fine while I'm there.
I thought this may have to do with my framebuffer setting on boot, so I got rid of that, which seems to cure the post-X problem (although now I have a standard screen that's ugly and hard to work on) but doesn't cure the initial boot problem. I'm using a framebuffer setting of 788, my video card doesn't like 773. Video Card is a Real Starfighter 3D AGP.
I had this monitor on another arch system, different AGP video card, and it worked fine.
Where does the system get its initial screen settings?