from the ultimarc siteSelecting a resolution for each game. 
TheArcadeVGA card has the following built-in resolutions:
H V Vertical Refresh 
240 240 60Hz 
256 240 60Hz 
256 256   
256 264   
288 240 60Hz 
296 240 60Hz 
304 240 60Hz 
320 200 60Hz (321 X 200 in Windows) 
320 240 60Hz (321 X 240 in Windows) 
320 256   
336 240 60Hz 
352 256 Vert on Horiz Mon 
352 264 Vert on Horiz Mon 
352 288 Vert on Horiz Mon 
368 240 60Hz 
392 240 60Hz 
384 288   
400 256 53Hz, Mortal Kombat etc (401 X 256 in Windows) 
448 240 60Hz 
512 240 60Hz 
512 288   
512 448 Vert on Horiz Mon 
512 512   
632 264   
640 240 60Hz 
640 400   
640 480 60Hz 
800 600   
These are in addition to all the normal VGA text/graphics modes.
NOTES:
Three of the resolutions are one pixel wider in Windows, as shown. This was necessary because these are native Direct-X double-scanned modes and we don't want double scanning so we need to use a slightly different value to prevent Windows from invoking double-scan. In fact only the Windows "name" of the resolution is different, they actually scan the correct number of pixels, 300 or 400.
The resolutions which show no vertical rate in the table have an arbitrary rate which is the result of scanning the required number of lines at 15Khz. They are mostly around 50Hz. Arcade monitor timings prevent these resolutions from being displayed at 60Hz.
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Rampy