In days of yore there was a spate of video cards, primarily PCI I believe, that allowed tinkering with video signals. Changing sync polarities and other sorts of weirdness.
Anyone know what I'm talking about? Anyone know which cards had the ability?
Many Matrox PCI cards have programmable DACs. The drivers allow you to specify signal parameters. That's how I get 1080p in NT 3.52 and OS/2.
Windows 3.1x, NT3. 5x, and OS/2 drivers hold these values in a text file called MGA.MON organized by monitor entries. You can modify the file, but you'll need to reboot the OS before using the changes.
NT 4 and Windows 9x use the graphics properties GUI to modify signal parameters. Not as easy to use, in my opinion.
Every car d does this to this day. I can go to my Nvidia control panel and configure custom resolution on 1660 right now.
Back in the day you could do that with Powerstrip https://www.audioholics.com/diy-audio/powerst … e-a-user-manual