Recently, I bought a Matrox G450 G45FMDVP32 PCI card on AliExpress. I tried using it with Windows 98 SE on a Lucky Star 5I-VX2B motherboard (Intel 430VX chipset) with a Socket 7 AMD 5k86 P90 90 MHz CPU.

At first, I had a problem with the drivers — for some reason, the Matrox driver installation 6.83 did not detect any devices, while Windows suggested installing the Standard VGA Driver. I manually selected the driver "Matrox Millennium G450 DualHead DVI PCI – English", and it installed correctly.

It works quite well so far. I’m using a DVI-to-HDMI cable to connect it to a modern Samsung LS27D600 monitor. This is the first video card that has successfully displayed the BIOS and DOS screens on this monitor.

One thing that’s a bit annoying: When switching to DOS mode from Windows, the image becomes unstable, and the monitor sometimes loses signal and turns off briefly before recovering. This doesn’t happen in pure DOS mode, so it’s likely related to how the Windows driver handles the video mode switch. I’d be happy if someone could advise me on how to fix or improve this behavior.

Vovichx wrote on 2025-10-28, 19:08:

...
At first, I had a problem with the drivers — for some reason, the Matrox driver installation 6.83 did not detect any devices, while Windows suggested installing the Standard VGA Driver. I manually selected the driver "Matrox Millennium G450 DualHead DVI PCI – English", and it installed correctly.
...

This problem was discussed by Phil, from PhilsComputerLab: https://youtu.be/ft6eoyxT1ik?si=FODYLvz7afAYQGQS

Vovichx wrote on 2025-10-28, 19:08:

One thing that’s a bit annoying: When switching to DOS mode from Windows, the image becomes unstable, and the monitor sometimes loses signal and turns off briefly before recovering. This doesn’t happen in pure DOS mode, so it’s likely related to how the Windows driver handles the video mode switch. I’d be happy if someone could advise me on how to fix or improve this behavior.

I recently discovered a nifty little DOS TSR utility by TheGreatCodeholio, called "VGA240.EXE".
It is part of a larger pack of utilities called doslib.. But this basically makes DOS run in 640x480@60Hz instead of 720x400@70Hz.

I found it very useful at fixing some "ugly pixels" in 320x200 and 640x400 resolutions, and DOS screen tearing issues that I had on my LCD on the VGA port. Maybe it works on DVI too..
Here's the discussion about it: VGA Capture Thread

It's not perfect, as it messes up some games that have some of their timings tied to the refresh rate; and even may reduce performance if you're using a PS/2 mouse (no problem on serial).
But it is what it is, and it MASSIVELY reduced screen tearing in DOS games, and made the LCD sync up very nicely.

There are many versions of this utility in the GitHub archive, and I only tried the one from Sep 25-2019 in the folder named "hw/vga/dos86s" as it's said to have the smallest memory footprint.
I have no clue how the other variants behave.

Does it support 640x480@70Hz? Would this fix the timing issues?

Only 60Hz from what I know. As it's made specifically to cater to LCDs and capture devices, so they can sync propperly to the signal.

Kahenraz wrote on 2025-10-29, 06:20:

Does it support 640x480@70Hz? Would this fix the timing issues?

I conducted a couple of tests on the Samsung LS27D600 monitor with a DVI-to-HDMI cable and the Fujitsu B19-7 monitor with DVI and VGA cables.

Samsung LS27D600

DVI-to-HDMI cable
Pure DOS: 642x480@60Hz - This is stable:

DOS app under Windows 98: 1246x480@60Hz - This is unstable:

Windows 98 desktop: Stable at any possible resolution.

Fujitsu B19-7

DVI cable
POST screen: 480p@60Hz - This is stable:

DOS app under Windows 98: Out of range, no picture.
Windows 98 desktop: Stable at any possible resolution.

VGA cable
POST screen: 640x350@70Hz - This is stable:

DOS app under Windows 98: 720x400@70Hz - This is stable:

Windows 98 desktop: Stable at any resolution. For the standard resolution of 1280x1024 on this monitor, I could enable a 75Hz refresh rate, which is cool.

I can conclude that the Fujitsu B19-7 with a VGA cable is the best choice in my case. All modes are stable.