View Full Version : changing DOS VGA- and/or Text-mode refresh rate

11th November 2002, 15:15
the following thread describes how to modify the PINS on a Matrox cards' BIOS (G400) to get 75 Hz vertical refresh in stead of the default 60 hz, in situations like Windows 2000/XP startup screen (with the scrolling bar). This method can also be used to change the refresh to anything you like, which might be very usefull for using fixed-sync monitors in DOS.


You can probably achieve the same effect on different cards, if the offset for the "VGA1 pixel clock" (and/or "VGA2 pixel clock") in the pins file is updated to the correct value.

for more information on BIOS/PINS modifications/updating, see GBM's site:

and use the search function of this forum to find valuable information!

Keep in mind that modifying your BIOS/PINS is at own risk, and can _EASILY_ mess up your card badly (as you can see in the thread linked here)... so, take absolute precaution by making an emergency disk with the Matrox BIOS tools, and have a spare PCI videocard ready to get screen output if/when your Matrox card's BIOS is corrupted. (and set primary VGA to PCI in the BIOS).

Also not recommended when you use DOS TV-Out capabilities of your card (like the G400 can), as that might/will conflict with this adjustment to the pins.