eric@mks.com (Eric Gisin) (01/24/90)
A recent article mentioned that most IBM VGA monitors will work in 800x600 mode. So I tryed it with our colour IBM monitor and an Orchid VGA, and it worked except for the loss of a few lines at the top and bottom. But I'm wondering if this is safe to do. Most VGA cards use a horizontal frequency higher than the standard 31.5 kHz in this mode. Orchid uses 35.5 or 37.24, for example. I thought it was not safe to change the horizontal frequency on fixed frequency monitors.
mcdonald@aries.scs.uiuc.edu (Doug McDonald) (01/24/90)
In article <1990Jan23.211547.3559@mks.com> eric@mks.com (Eric Gisin) writes: >A recent article mentioned that most IBM VGA monitors >will work in 800x600 mode. So I tryed it with our colour IBM monitor >and an Orchid VGA, and it worked except for the loss of a few lines >at the top and bottom. > >But I'm wondering if this is safe to do. Most VGA cards use >a horizontal frequency higher than the standard 31.5 kHz in this mode. >Orchid uses 35.5 or 37.24, for example. >I thought it was not safe to change the horizontal frequency >on fixed frequency monitors. My IBM (8513) monitor wouldn't sync at 600x800. But it would in 540x720 mode. This mode on the IBM motherboard VGA I used had the same horizontal frequency as 480x640, so that is for sure OK. It was used for months and months so the vertical change appears to be OK also. Doug McDonald