Hello, here are a few modelines for dosbox on XFree86 or X.org servers. They provide display timings that are -- as far as I could find out -- identical to those of original VGA/SVGA hardware. This has the nice effect that almost any monitor will recognize the timing as "known" and will do something more or less sensible with it. Also, many monitors have a limited number of "user modes" for which they can remember the OSD settings (such as picture size and position, pin cushion correction, trapezoid correction etc.). On a dual-boot machine that has e.g. some dedicated DVD playback modes thrown into the picture, monitors run out of user modes very quickly, which turns the poor user into an OSD setting machine. Using "known" modes instead reduces this problem a lot. You can do that by putting the right "Modelines" into your X server configuration file.

If you've never heard of Modelines, it might be better not to try and use this, as you can easily mess up your X configuration and/or fry your monitor by screwing up. You've been warned!

Here are the three modelines that cover all standard VGA modes:

1#Modes for VGA emulation
2Modeline "640x350" 25.175 640 656 752 800 350 387 389 449 +HSync -VSync
3Modeline "640x400" 25.175 640 656 752 800 400 412 414 449 -HSync +VSync 
4Modeline "640x480" 25.175 640 656 752 800 480 490 492 525 -HSync -VSync

Information source: http://www.epanorama.net/documents/pc/vga_timing.html

These modes are tested and working on my monitor and card. Your server and card driver *must* honor the sync polarity keywords for this to work; some don't.

Here are a couple of SVGA modelines, converted from the Matrox-distributed mon.inf file:

1# Modes for SVGA emulation
2Modeline "640x480" 30.5 640 672 768 864 480 517 523 588 +HSync +VSync
3Modeline "800x600" 38.1 800 832 960 1088 600 602 606 620 +HSync +VSync
4Modeline "1024x768" 46.6 1024 1088 1216 1312 768 770 776 808 +HSync +VSync Interlace

The last of these will work only if your server and card driver can do interlaced modes; many can't. Note that the SVGA 640x480 timing is different from the VGA 640x480 timing. Also note that far fewer current monitors "know" these modes compared to the VGA modes given above. Their main use is in driving older monitors.

EDIT: On Windows you can do the same with PowerStrip. Just select advanced custom timings and enter the timings given on the website above. I had to create the 640x350 mode as a "custom mode" since it's not a standard resolution in most drivers, but it works very well too.